Wenxing Fang

The production of Z bosons in pPb collisions at sqrt(s[NN]) = 5.02 TeV is studied by the CMS experiment via the electron and muon decay channels. The inclusive cross section is compared to pp collision predictions, and found to scale with the number of elementary nucleon-nucleon collisions. The differential cross sections as a function of the Z boson rapidity and transverse momentum are measured. Though they are found to be consistent within uncertainty with theoretical predictions both with and without nuclear effects, the forward-backward asymmetry suggests the presence of nuclear effects at large rapidities. These results provide new data for constraining nuclear parton distribution functions.

Based on 10 billion J/ψ events collected at the BESIII experiment, a search for CP violation in Λ decay is performed in the difference between CP-odd decay parameters α_{-} for Λ→pπ^{-} and α_{+} for Λ[over ¯]→p[over ¯]π^{+} by using the process e^{+}e^{-}→J/ψ→ΛΛ[over ¯]. With a five-dimensional fit to the full angular distributions of the daughter baryon, the most precise values for the decay parameters are determined to be α_{-}=0.7519±0.0036±0.0024 and α_{+}=-0.7559±0.0036±0.0030, respectively. The Λ and Λ[over ¯] averaged value of the decay parameter is extracted to be α_{avg}=0.7542±0.0010±0.0024 with unprecedented accuracy. The CP asymmetry A_{CP}=(α_{-}+α_{+})/(α_{-}-α_{+}) is determined to be -0.0025±0.0046±0.0012, which is one of the most precise measurements in the baryon sector. The reported results for the decay parameter will play an important role in the studies of the polarizations and CP violations for the strange, charmed and beauty baryons.

Abstract The cross sections of <?CDATA $ e^+e^- \rightarrow K^+K^-J/\psi $?> at center-of-mass energies from 4.127 to 4.600 GeV are measured based on 15.6 fb <?CDATA $ ^{-1} $?> data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in the line shape of the cross sections. The mass and width of the first structure are measured to be ( <?CDATA $ 4225.3\pm2.3\pm21.5 $?> ) MeV and ( <?CDATA $ 72.9\pm6.1\pm30.8 $?> ) MeV, respectively. They are consistent with those of the established <?CDATA $ Y(4230) $?> . The second structure is observed for the first time with a statistical significance greater than 8 σ , denoted as <?CDATA $ Y(4500) $?> . Its mass and width are determined to be ( <?CDATA $ 4484.7\pm13.3\pm24.1 $?> ) MeV and ( <?CDATA $ 111.1\pm30.1\pm15.2 $?> ) MeV, respectively. The first presented uncertainties are statistical and the second ones are systematic. The product of the electronic partial width with the decay branching fraction <?CDATA $ \Gamma(Y(4230)\to e^+ e^-) \mathcal{B}(Y(4230) \to K^+ K^- J/\psi) $?> is reported.

Abstract Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 fb <?CDATA $ ^{-1} $?> , collected by the BESIII detector in the energy region between <?CDATA $ 4599.53\; \,{\rm{MeV}} $?> and <?CDATA $ 4698.82\; \,{\rm{MeV}} $?> , we report the first observations of the Cabibbo-suppressed decays <?CDATA $ \Lambda_c^+\to n\pi^+\pi^0 $?> , <?CDATA $ \Lambda_c^+\to n\pi^+\pi^-\pi^+ $?> , and the Cabibbo-favored decay <?CDATA $ \Lambda_c^+\to nK^-\pi^+\pi^+ $?> with statistical significances of <?CDATA $ 7.9\sigma $?> , <?CDATA $ 7.8\sigma $?> , and <?CDATA $ &gt;10\sigma $?> , respectively. The branching fractions of these decays are measured to be <?CDATA $\mathcal{B}(\Lambda_{c}^{+}\rightarrow n\pi^{+}\pi^{0})=(0.64\pm0.09\pm0.02)$?> %, <?CDATA $\mathcal{B}(\Lambda_{c}^{+}\rightarrow n\pi^{+}\pi^{-}\pi^{+})=(0.45\pm 0.07\pm $?> <?CDATA $ 0.03)$?> %, and <?CDATA $\mathcal{B}(\Lambda_{c}^{+}\rightarrow nK^{-}\pi^{+}\pi^{+})=(1.90\pm0.08\pm0.09)$?> %, where the first uncertainties are statistical and the second are systematic. We find that the branching fraction of the decay <?CDATA $ \Lambda_{c}^{+}\rightarrow n\pi^{+}\pi^{0} $?> is about one order of magnitude higher than that of <?CDATA $ \Lambda_{c}^{+}\rightarrow n\pi^{+} $?> .

Using initial-state radiation events from a total integrated luminosity of 11.957 fb−1 of e+e− collision data collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector at BEPCII, the cross section for the process e+e−→Λ¯Λ is measured in 16 Λ¯Λ invariant mass intervals from the production threshold up to 3.00 GeV/c2. The results are consistent with previous results from BABAR and BESIII, but with better precision and with narrower Λ¯Λ invariant mass intervals than BABAR.1 MoreReceived 15 March 2023Accepted 23 March 2023Corrected 28 April 2023DOI:https://doi.org/10.1103/PhysRevD.107.072005Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasForm factorsParticle interactionsQuantum chromodynamicsQuark matterPhysical SystemsBaryonsLight quarksStrange quarkTechniquesLepton collidersMonte Carlo methodsParticle productionParticles & Fields

We search for an axion-like particle (ALP) $a$ through the process $\psi(3686)\rightarrow\pi^+\pi^-J/\psi$, $J/\psi\rightarrow\gamma a$, $a\rightarrow\gamma\gamma$ in a data sample of $(2.71\pm0.01)\times10^9$ $\psi(3686)$ events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay $J/\psi\rightarrow\gamma a$ and the ALP-photon coupling constant $g_{a\gamma\gamma}$ are set at 95% confidence level in the mass range of $0.165\leq m_a\leq2.84\,\mbox{GeV}/c^2$. The limits on $B(J/\psi\rightarrow\gamma a)$ range from $8.3\times10^{-8}$ to $1.8\times10^{-6}$ over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for $0.165\leq m_a\leq1.468\,\mbox{GeV}/c^2$.

The Born cross sections of the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{*0}{D}^{*\ensuremath{-}}{\ensuremath{\pi}}^{+}$ at center-of-mass energies from 4.189 to 4.951 GeV are measured for the first time. The data samples used correspond to an integrated luminosity of $17.9\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ and were collected by the BESIII detector operating at the BEPCII storage ring. Three enhancements around 4.20, 4.47, and 4.67 GeV are visible. The resonances have masses of $4209.6\ifmmode\pm\else\textpm\fi{}4.7\ifmmode\pm\else\textpm\fi{}5.9\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, $4469.1\ifmmode\pm\else\textpm\fi{}26.2\ifmmode\pm\else\textpm\fi{}3.6\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, and $4675.3\ifmmode\pm\else\textpm\fi{}29.5\ifmmode\pm\else\textpm\fi{}3.5\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and widths of $81.6\ifmmode\pm\else\textpm\fi{}17.8\ifmmode\pm\else\textpm\fi{}9.0\text{ }\text{ }\mathrm{MeV}$, $246.3\ifmmode\pm\else\textpm\fi{}36.7\ifmmode\pm\else\textpm\fi{}9.4\text{ }\text{ }\mathrm{MeV}$, and $218.3\ifmmode\pm\else\textpm\fi{}72.9\ifmmode\pm\else\textpm\fi{}9.3\text{ }\text{ }\mathrm{MeV}$, respectively, where the first uncertainties are statistical and the second systematic. The first and third resonances are consistent with the $\ensuremath{\psi}(4230)$ and $\ensuremath{\psi}(4660)$ states, respectively, while the second one is compatible with the $\ensuremath{\psi}(4500)$ observed in the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}J/\ensuremath{\psi}$ process. These three charmoniumlike $\ensuremath{\psi}$ states are observed in the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{*0}{D}^{*\ensuremath{-}}{\ensuremath{\pi}}^{+}$ process for the first time.

Using a data sample of (10087±44)×106 J/ψ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process J/ψ→e+e−η(1405) is observed via the decay η(1405)→π0f0(980), f0(980)→π+π−, with a significance of about 9.8σ. The branching fraction of this decay is measured to be B(J/ψ→e+e−η(1405)→e+e−π0f0(980)→e+e−π0π+π−)=(2.04±0.20(stat)±0.08(syst))×10−7. The branching fraction ratio B(J/ψ→e+e−η(1405))/B(J/ψ→γη(1405)) is determined to be (1.36±0.17(stat)±0.06(syst))×10−2. Furthermore, an e+e− invariant mass dependent transition form factor of J/ψ→e+e−η(1405) is presented for the first time. The obtained result provides input for different theoretical models and is valuable for the improved understanding the intrinsic structure of the η(1405) meson.Received 28 July 2023Accepted 27 November 2023DOI:https://doi.org/10.1103/PhysRevD.109.012007Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionForm factorsLeptonic, semileptonic & radiative decaysParticle decaysPhysical SystemsCharm quarkParticles & Fields

The first observation of the decays J/ψ→p¯Σ+KS0 and J/ψ→pΣ¯−KS0 is reported using (10087±44)×106 J/ψ events recorded by the BESIII detector at the BEPCII storage ring. The branching fractions of each channel are determined to be B(J/ψ→p¯Σ+KS0)=(1.361±0.006±0.025)×10−4, and B(J/ψ→pΣ¯−KS0)=(1.352±0.006±0.025)×10−4. The combined result is B(J/ψ→p¯Σ+KS0+c.c.)=(2.725±0.009±0.050)×10−4, where the first uncertainty is statistical and the second systematic. The results presented are in good agreement with the branching fractions of the isospin partner decay J/ψ→pK−Σ¯0+c.c.Received 14 November 2023Accepted 14 December 2023DOI:https://doi.org/10.1103/PhysRevD.109.012006Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle interactionsStrong interactionPhysical SystemsBaryonsHyperonsTechniquesParticle data analysisParticles & Fields

Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-boson-exchange decay Λc+→Ξ0K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be αΞ0K+=0.01±0.16(stat)±0.03(syst). This result reflects the noninterference effect between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes has two solutions, which are δp−δs=−1.55±0.25(stat)±0.05(syst) rad or 1.59±0.25(stat)±0.05(syst) rad.Received 6 September 2023Accepted 30 November 2023DOI:https://doi.org/10.1103/PhysRevLett.132.031801Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectroweak interactionHadronic decaysPolarization in interactions & scatteringPhysical SystemsHyperonsW & Z bosonsParticles & Fields

Based on a data sample of (2712.4±14.3)×106ψ(3686) events collected with the BESIII detector at the BEPCII collider, the M1 transition ψ(3686)→γηc(2S) with ηc(2S)→KK¯π is studied, where KK¯π is K+K−π0 or KS0K±π∓. The mass and width of the ηc(2S) are measured to be (3637.8±0.8(stat)±0.2(syst)) MeV/c2 and (10.5±1.7(stat)±3.5(syst)) MeV, respectively. The product branching fraction B(ψ(3686)→γηc(2S))×B(ηc(2S)→KK¯π) is determined to be (0.97±0.06(stat)±0.09(syst))×10−5. Using B(ηc(2S)→KK¯π)=(1.86−0.49+0.68)%, we obtain the branching fraction of the radiative transition to be B(ψ(3686)→γηc(2S))=(5.2±0.3(stat)±0.5(syst)−1.4+1.9(extr))×10−4, where the third uncertainty is due to the quoted B(ηc(2S)→KK¯π).Received 26 September 2023Accepted 8 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.032004Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionLeptonic, semileptonic & radiative decaysQuark modelPhysical SystemsQuarkoniaParticles & Fields

By analyzing 7.33 fb−1 of e+e− annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay Ds+→η′μ+νμ, with a statistical significance larger than 10σ, and the measurements of the Ds+→ημ+νμ and Ds+→η′μ+νμ decay dynamics for the first time. The branching fractions of Ds+→ημ+νμ and Ds+→η′μ+νμ are determined to be (2.235±0.051stat±0.052syst)% and (0.801±0.055stat±0.028syst)%, respectively, with precision improved by factors of 6.0 and 6.6 compared to the previous best measurements. Combined with the results for the decays Ds+→ηe+νe and Ds+→η′e+νe, the ratios of the decay widths are examined both inclusively and in several ℓ+νℓ four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors f+,0η(′)(0) and the c→s Cabibbo-Kobayashi-Maskawa matrix element |Vcs| are determined. The results based on the two-parameter series expansion are f+,0η(0)|Vcs|=0.452±0.010stat±0.007syst and f+,0η′(0)|Vcs|=0.504±0.037stat±0.012syst, which help to constrain present models on f+,0η(′)(0). The forward-backward asymmetries are determined to be ⟨AFBη⟩=−0.059±0.031stat±0.005syst and ⟨AFBη′⟩=−0.064±0.079stat±0.006syst for the first time, which are consistent with the theoretical calculation.Received 25 July 2023Revised 25 January 2024Accepted 26 January 2024DOI:https://doi.org/10.1103/PhysRevLett.132.091802Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionLeptonic, semileptonic & radiative decaysParticle interactionsQuark mixingPhysical SystemsCharmed mesonsPropertiesFlavor symmetriesForm factorsParticles & Fields

Using a sample of (10087±44)×10^{6} J/ψ events, which is about 45 times larger than that was previously analyzed, a further investigation on the J/ψ→γ3(π^{+}π^{-}) decay is performed. A significant distortion at 1.84 GeV/c^{2} in the line shape of the 3(π^{+}π^{-}) invariant mass spectrum is observed for the first time, which could be resolved by two overlapping resonant structures, X(1840) and X(1880). The new state X(1880) is observed with a statistical significance larger than 10σ. The mass and width of X(1880) are determined to be 1882.1±1.7±0.7 MeV/c^{2} and 30.7±5.5±2.4 MeV, respectively, which indicates the existence of a pp[over ¯] bound state.

We study the processes e^{+}e^{-}→K_{S}^{0}D_{s}^{+}D^{*-} and e^{+}e^{-}→K_{S}^{0}D_{s}^{*+}D^{-}, as well as their charge conjugated processes, at five center-of-mass energies between 4.628 and 4.699 GeV, using data samples corresponding to an integrated luminosity of 3.8 fb^{-1} collected by the BESIII detector at the BEPCII storage ring. Based on a partial reconstruction technique, we find evidence of a structure near the thresholds for D_{s}^{+}D^{*-} and D_{s}^{*+}D^{-} production in the K_{S}^{0} recoil-mass spectrum, which we refer to as the Z_{cs}(3985)^{0}. Fitting with a Breit-Wigner line shape, we find the mass of the structure to be (3992.2±1.7±1.6) MeV/c^{2} and the width to be (7.7_{-3.8}^{+4.1}±4.3) MeV, where the first uncertainties are statistical and the second are systematic. The significance of the Z_{cs}(3985)^{0} signal is found to be 4.6σ including both the statistical and systematic uncertainty. We report the Born cross section multiplied by the branching fraction at different energy points. The mass of the Z_{cs}(3985)^{0} is close to that of the Z_{cs}(3985)^{+}. Assuming SU(3) symmetry, the cross section of the neutral channel is consistent with that of the charged one. Hence, we conclude that the Z_{cs}(3985)^{0} is the isospin partner of the Z_{cs}(3985)^{+}.

The study of the Cabibbo-favored semileptonic decay Λ_{c}^{+}→Λe^{+}ν_{e} is reported using a 4.5 fb^{-1} data sample of e^{+}e^{-} annihilations collected at center-of-mass energies ranging from 4.600 GeV to 4.699 GeV with the BESIII detector at the BEPCII collider. The branching fraction of the decay is measured to be B(Λ_{c}^{+}→Λe^{+}ν_{e})=(3.56±0.11_{stat}±0.07_{syst})%, which is the most precise measurement to date. Furthermore, we perform an investigation of the internal dynamics in Λ_{c}^{+}→Λe^{+}ν_{e}. We provide the first direct comparisons of the differential decay rate and form factors with those predicted from lattice quantum chromodynamics (LQCD) calculations. Combining the measured branching fraction with a q^{2}-integrated rate predicted by LQCD, we determine |V_{cs}|=0.936±0.017_{B}±0.024_{LQCD}±0.007_{τ_{Λ_{c}}}.

Using data samples of e+e− collisions collected with the BESIII detector at eight center-of-mass energy points between 3.49 and 3.67 GeV, corresponding to an integrated luminosity of 670 pb−1, we present the upper limits of Born cross sections and the effective form factor for the process e+e−→Ω−¯Ω+. A fit to the cross sections using a perturbative QCD-derived energy-dependent function shows no significant threshold effect. The upper limit on the measured effective form factor is consistent with a theoretical prediction within the uncertainty of 1σ. These results provide new experimental information on the production mechanism of Ω.Received 7 December 2022Accepted 5 January 2023DOI:https://doi.org/10.1103/PhysRevD.107.052003Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Particle interactionsResearch AreasParticle phenomenaParticle interactionsResearch AreasForm factorsParticle interactionsTotal cross sectionsParticles & Fields

The J/ψ→Ξ0¯Ξ0 process and subsequent decays are investigated using (10087±44)×106 J/ψ events collected at the BESIII experiment. The decay parameters of Ξ0 and ¯Ξ0 are simultaneously measured to be αΞ=−0.3750±0.0034±0.0016, ¯αΞ=0.3790±0.0034±0.0021, ϕΞ=0.0051±0.0096±0.0018 rad, ¯ϕΞ=−0.0053±0.0097±0.0019 rad with unprecedented accuracies, where the first and the second uncertainties are statistical and systematic, respectively. The most precise values for CP asymmetry observables of Ξ0 decay are obtained to be AΞCP=(−5.4±6.5±3.1)×10−3 and ΔϕΞCP=(−0.1±6.9±0.9)×10−3 rad. For the first time, the weak and strong phase differences are determined to be ξP−ξS=(0.0±1.7±0.2)×10−2 rad and δP−δS=(−1.3±1.7±0.4)×10−2 rad, which are the most precise results for any weakly decaying baryon. These results will play important roles in the studies of the CP violations and polarizations for the strange, charmed, and beauty baryons.Received 16 May 2023Revised 4 June 2023Accepted 20 July 2023DOI:https://doi.org/10.1103/PhysRevD.108.L031106Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHadronic decaysPhysical SystemsHyperonsPropertiesCP violationPolarizationParticles & Fields

The process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{s}^{*+}{D}_{s}^{*\ensuremath{-}}$ is studied with a semi-inclusive method using data samples at center-of-mass energies from threshold to 4.95 GeV collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections of the process are measured for the first time with high precision in this energy region. Two resonance structures are observed in the energy-dependent cross sections around 4.2 and 4.4 GeV. By fitting the cross sections with a coherent sum of three Breit-Wigner amplitudes and one phase-space amplitude, the two significant structures are assigned masses of $(4186.8\ifmmode\pm\else\textpm\fi{}8.7\ifmmode\pm\else\textpm\fi{}30)$ and $(4414.6\ifmmode\pm\else\textpm\fi{}3.4\ifmmode\pm\else\textpm\fi{}6.1)\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, widths of $(55\ifmmode\pm\else\textpm\fi{}15\ifmmode\pm\else\textpm\fi{}53)$ and $(122.5\ifmmode\pm\else\textpm\fi{}7.5\ifmmode\pm\else\textpm\fi{}8.1)\text{ }\text{ }\mathrm{MeV}$, where the first errors are statistical and the second ones are systematic. The inclusion of a third Breit-Wigner amplitude is necessary to describe a structure around 4.79 GeV.

Abstract We report a search for a heavier partner of the recently observed <?CDATA $ Z_{cs}(3985)^{-} $?> state, denoted as <?CDATA $ Z_{cs}^{\prime -} $?> , in the process <?CDATA $ e^{+} e^{-}\rightarrow K^{+}D_{s}^{*-}D^{* 0}+c.c. $?> , based on <?CDATA $ e^+e^- $?> collision data collected at the center-of-mass energies of <?CDATA $ \sqrt{s}=4.661 $?> , 4.682 and 4.699 GeV with the BESIII detector. The <?CDATA $ Z_{cs}^{\prime -} $?> is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate <?CDATA $ K^+ $?> recoil-mass spectra, which are probed for a potential contribution from <?CDATA $ Z_{cs}^{\prime -}\to D_{s}^{*-}D^{* 0} $?> ( <?CDATA $ c.c. $?> ). We find an excess of <?CDATA $ Z_{cs}^{\prime -}\rightarrow D_{s}^{*-}D^{*0} $?> ( <?CDATA $ c.c. $?> ) candidates with a significance of <?CDATA $ 2.1\sigma $?> , after considering systematic uncertainties, at a mass of <?CDATA $ (4123.5\pm0.7_\mathrm{stat.}\pm4.7_\mathrm{syst.}) \,\mathrm{MeV}/c^2 $?> . As the data set is limited in size, the upper limits are evaluated at the 90% confidence level on the product of the Born cross sections ( <?CDATA $ \sigma^{\mathrm{Born}} $?> ) and the branching fraction ( <?CDATA $ \mathcal{B} $?> ) of <?CDATA $ Z_{cs}^{\prime-}\rightarrow D_{s}^{*-}D^{* 0} $?> , under different assumptions of the <?CDATA $ Z_{cs}^{\prime -} $?> mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies. The upper limits of <?CDATA $ \sigma^{\rm Born}\cdot\mathcal{B} $?> are found to be at the level of <?CDATA $ \mathcal{O}(1) $?> pb at each energy. Larger data samples are needed to confirm the <?CDATA $ Z_{cs}^{\prime -} $?> state and clarify its nature in the coming years.

Inclusive jet production in pPb collisions at a nucleon-nucleon (NN) center-of-mass energy of sqrt(s[NN]) = 5.02 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 35 inverse nanobarns is analyzed. The jet transverse momentum spectra are studied in seven pseudorapidity intervals covering the range -2.0 &lt; eta[CM] &lt; 1.5 in the NN center-of-mass frame. The jet production yields at forward and backward pseudorapidity are compared and no significant asymmetry about eta[CM] = 0 is observed in the measured kinematic range. The measurements in the pPb system are compared to reference jet spectra obtained by extrapolation from previous measurements in pp collisions at sqrt(s) = 7 TeV. In all pseudorapidity ranges, nuclear modifications in inclusive jet production are found to be small, as predicted by next-to-leading order perturbative QCD calculations that incorporate nuclear effects in the parton distribution functions.

A search is presented for single top quark production in the s channel in proton-proton collisions with the CMS detector at the CERN LHC in decay modes of the top quark containing a muon or an electron in the final state. The signal is extracted through a maximum-likelihood fit to the distribution of a multivariate discriminant defined using boosted decision trees to separate the expected signal contribution from background processes. The analysis uses data collected at centre-of-mass energies of 7 and 8 TeV and corresponding to integrated luminosities of 5.1 and 19.7 fb−1, respectively. The measured cross sections of 7.1 ± 8.1 pb (at 7 TeV) and 13.4 ± 7.3 pb (at 8 TeV) result in a best fit value of 2.0 ± 0.9 for the combined ratio of the measured and expected values. The signal significance is 2.5 standard deviations, and the upper limit on the rate relative to the standard model expectation is 4.7 at 95% confidence level.

We report a search for a dark photon using $14.9$~fb$^{-1}$ of $e^+e^-$ annihilation data taken at center-of-mass energies from 4.13 to 4.60~GeV with the BESIII detector operated at the BEPCII storage ring. The dark photon is assumed to be produced in the radiative annihilation process of $e^+e^-$ and to predominantly decay into light dark matter particles, which escape from the detector undetected. The mass range from 1.5 to 2.9~GeV is scanned for the dark photon candidate, and no significant signal is observed. The mass dependent upper limits at the 90$\%$ confidence level on the coupling strength parameter $\epsilon$ for a dark photon coupling with an ordinary photon vary between $1.6\times 10^{-3}$ and $5.7\times10^{-3}$.

Using a sample of 4.3×10^{5} η^{'}→ηπ^{0}π^{0} events selected from the ten billion J/ψ event dataset collected with the BESIII detector, we study the decay η^{'}→ηπ^{0}π^{0} within the framework of nonrelativistic effective field theory. Evidence for a structure at π^{+}π^{-} mass threshold is observed in the invariant mass spectrum of π^{0}π^{0} with a statistical significance of around 3.5σ, which is consistent with the cusp effect as predicted by the nonrelativistic effective field theory. After introducing the amplitude for describing the cusp effect, the ππ scattering length combination a_{0}-a_{2} is determined to be 0.226±0.060_{stat}±0.013_{syst}, which is in good agreement with theoretical calculation of 0.2644±0.0051.

We present the first measurements of the electric and magnetic form factors of the neutron in the timelike (positive q^{2}) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e^{+}e^{-}→n[over ¯]n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6 pb^{-1} in total at twelve center-of-mass energies between sqrt[s]=2.0-2.95 GeV. A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at sqrt[s]=2.3935 GeV. Our results are comparable in accuracy to those from electron scattering in the comparable spacelike region of four-momentum transfer. The electromagnetic form factor ratio R_{em}≡|G_{E}|/|G_{M}| is within the uncertainties close to unity. We compare our result on |G_{E}| and |G_{M}| to recent model predictions, and the measurements in the spacelike region to test the analyticity of electromagnetic form factors.

Based on ${e}^{+}{e}^{\ensuremath{-}}$ collision data corresponding to an integrated luminosity of $4.5\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected at the center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII, the absolute branching fraction of the inclusive decay ${\overline{\mathrm{\ensuremath{\Lambda}}}}_{c}^{\ensuremath{-}}\ensuremath{\rightarrow}\overline{n}+X$, where $X$ refers to any possible final state particles, is measured. The absolute branching fraction is determined to be $\mathcal{B}({\overline{\mathrm{\ensuremath{\Lambda}}}}_{c}^{\ensuremath{-}}\ensuremath{\rightarrow}\overline{n}+X)=(32.4\ifmmode\pm\else\textpm\fi{}0.7\ifmmode\pm\else\textpm\fi{}1.5)%$, where the first uncertainty is statistical and the second systematic. Assuming $CP$ symmetry, the measurement indicates that about one fourth of ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}$ (${\overline{\mathrm{\ensuremath{\Lambda}}}}_{c}^{\ensuremath{-}}$) decay modes with a neutron (an antineutron) in the final state have not been observed.

Precision measurements of the semileptonic decays Ds+→ηe+νe and Ds+→η′e+νe are performed with 7.33 fb−1 of e+e− collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector. The branching fractions obtained are B(Ds+→ηe+νe)=(2.255±0.039stat±0.051syst)% and B(Ds+→η′e+νe)=(0.810±0.038stat±0.024syst)%. Combining these results with the B(D+→ηe+νe) and B(D+→η′e+νe) obtained from previous BESIII measurements, the η−η′ mixing angle in the quark flavor basis is determined to be ϕP=(40.0±2.0stat±0.6syst)°. Moreover, from the fits to the partial decay rates of Ds+→ηe+νe and Ds+→η′e+νe, the products of the hadronic transition form factors f+η(′)(0) and the modulus of the c→s Cabibbo-Kobayashi-Maskawa matrix element |Vcs| are determined by using different hadronic transition form factor parametrizations. Based on the two-parameter series expansion, the products f+η(0)|Vcs|=0.4519±0.0071stat±0.0065syst and f+η′(0)|Vcs|=0.525±0.024stat±0.009syst are extracted. All results determined in this work supersede those measured in the previous BESIII analyses based on the 3.19 fb−1 subsample of data at 4.178 GeV.2 MoreReceived 8 June 2023Accepted 8 September 2023DOI:https://doi.org/10.1103/PhysRevD.108.092003Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionForm factorsLeptonic, semileptonic & radiative decaysParticle decaysParticle interactionsQuark mixingPhysical SystemsCharmed mesonsTechniquesLepton collidersParticles & Fields

Using data samples with an integrated luminosity of 5.85 fb−1 collected at center-of-mass energies from 4.61 to 4.95 GeV with the BESIII detector operating at the BEPCII storage ring, we measure the cross section for the process e+e−→K+K−J/ψ. A new resonance with a mass of M=4708−15+17±21 MeV/c2 and a width of Γ=126−23+27±30 MeV is observed in the energy-dependent line shape of the e+e−→K+K−J/ψ cross section with a significance over 5σ. The K+J/ψ system is also investigated to search for charged charmoniumlike states, but no significant Zcs+ states are observed. Upper limits on the Born cross sections for e+e−→K−Zcs(3985)+/K−Zcs(4000)++c.c. with Zcs(3985)±/Zcs(4000)±→K±J/ψ are reported at 90% confidence levels. The ratio of branching fractions {[B(Zcs(3985)+→K+J/ψ)]/B[Zcs(3985)+→(D¯0Ds*++D¯*0Ds+)]} is measured to be less than 0.03 at 90% confidence level.Received 31 August 2023Accepted 30 October 2023DOI:https://doi.org/10.1103/PhysRevLett.131.211902Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadron productionHadronic decaysMultiquark bound statesStrong interactionTotal cross sectionsPhysical SystemsHadronsTechniquesLepton collidersParticles & Fields

A search for narrow resonances decaying to an electron and a muon is presented. The $$\mathrm {e}$$ $${\mu }$$ mass spectrum is also investigated for non-resonant contributions from the production of quantum black holes (QBHs). The analysis is performed using data corresponding to an integrated luminosity of 19.7 $$~\text {fb}^\text {-1}$$ collected in proton-proton collisions at a centre-of-mass energy of 8 $$~\text {TeV}$$ with the CMS detector at the LHC. With no evidence for physics beyond the standard model in the invariant mass spectrum of selected $$\mathrm {e}\mu $$ pairs, upper limits are set at 95 $$\%$$ confidence level on the product of cross section and branching fraction for signals arising in theories with charged lepton flavour violation. In the search for narrow resonances, the resonant production of a $$\mathrm {\tau }$$ sneutrino in R-parity violating supersymmetry is considered. The $$\mathrm {\tau }$$ sneutrino is excluded for masses below 1.28 $$~\text {TeV}$$ for couplings $$\lambda _{132}=\lambda _{231}=\lambda '_{311}=0.01$$ , and below 2.30 $$~\text {TeV}$$ for $$\lambda _{132}=\lambda _{231}=0.07$$ and $$\lambda '_{311}=0.11$$ . These are the most stringent limits to date from direct searches at high-energy colliders. In addition, the resonance searches are interpreted in terms of a model with heavy partners of the $${\mathrm {Z}} $$ boson and the photon. In a framework of TeV-scale quantum gravity based on a renormalization of Newton’s constant, the search for non-resonant contributions to the $$\mathrm {e}$$ $${\mu }$$ mass spectrum excludes QBH production below a threshold mass $$M_{\mathrm {th}}$$ of 1.99 $$~\text {TeV}$$ . In models that invoke extra dimensions, the bounds range from 2.36 $$~\text {TeV}$$ for one extra dimension to 3.63 $$~\text {TeV}$$ for six extra dimensions. This is the first search for QBHs decaying into the $$\mathrm {e}$$ $${\mu }$$ final state.

The accurate identification of irreversible infarction and salvageable tissue is important in planning the treatments for acute ischemic stroke (AIS) patients. Computed tomographic perfusion (CTP) can be used to evaluate the ischemic core and deficit, covering most of the territories of anterior circulation, but many community hospitals and primary stroke centers do not have the capability to perform CTP scan in emergency situation. This study aimed to identify AIS lesions from widely available non-contrast computed tomography (NCCT) and CT angiography (CTA) using deep learning. A total of 345AIS patients from our emergency department were included. A multi-scale 3D convolutional neural network (CNN) was used as the predictive model with inputs of NCCT, CTA, and CTA+ (8 s delay after CTA) images. An external cohort with 108 patients was included to further validate the generalization performance of the proposed model. Strong correlations with CTP-RAPID segmentations (r = 0.84 for core, r = 0.83 for deficit) were observed when NCCT, CTA, and CTA+ images were all used in the model. The diagnostic decisions according to DEFUSE3 showed high accuracy when using NCCT, CTA, and CTA+ (0.90±0.04), followed by the combination of NCCT and CTA (0.87±0.04), CTA-alone (0.76±0.06), and NCCT-alone (0.53±0.09).

Using a sample of $(448.1\ifmmode\pm\else\textpm\fi{}2.9)\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{ }\ensuremath{\psi}(3686)$ decays collected with the BESIII detector at BEPCII, we report an observation of ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}$ transverse polarization with a significance of $7.3\ensuremath{\sigma}$ in the decay $\ensuremath{\psi}(3686)\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}{\overline{\mathrm{\ensuremath{\Xi}}}}^{+}$ (${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{\ensuremath{-}}$, ${\overline{\mathrm{\ensuremath{\Xi}}}}^{+}\ensuremath{\rightarrow}\overline{\mathrm{\ensuremath{\Lambda}}}{\ensuremath{\pi}}^{+}$, $\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}$, $\overline{\mathrm{\ensuremath{\Lambda}}}\ensuremath{\rightarrow}\overline{p}{\ensuremath{\pi}}^{+}$). The relative phase of the electric and magnetic form factors is determined to be $\mathrm{\ensuremath{\Delta}}\mathrm{\ensuremath{\Phi}}=(0.667\ifmmode\pm\else\textpm\fi{}0.111\ifmmode\pm\else\textpm\fi{}0.058)\text{ }\text{ }\mathrm{rad}$. This is the first measurement of the relative phase for a $\ensuremath{\psi}(3686)$ decay into a pair of ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}{\overline{\mathrm{\ensuremath{\Xi}}}}^{+}$ hyperons. The ${\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}$ decay parameters (${\ensuremath{\alpha}}_{{\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}}$, ${\ensuremath{\phi}}_{{\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}}$) and their conjugates (${\ensuremath{\alpha}}_{{\overline{\mathrm{\ensuremath{\Xi}}}}^{+}}$, ${\ensuremath{\phi}}_{{\overline{\mathrm{\ensuremath{\Xi}}}}^{+}}$), the angular-distribution parameter ${\ensuremath{\alpha}}_{\ensuremath{\psi}}$, and the strong-phase difference ${\ensuremath{\delta}}_{p}\ensuremath{-}{\ensuremath{\delta}}_{s}$ for $\mathrm{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{\ensuremath{-}}$ scattering are measured to be consistent with previous BESIII results.

Using $4.5~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data samples collected at the center-of-mass energies ranging from 4.600~GeV to 4.699~GeV with the BESIII detector at the BEPCII collider, a first study of the semileptonic decays $\Lambda_c^+\rightarrow pK^-e^+\nu_e$, $\Lambda_c^+\rightarrow \Lambda(1520) e^+\nu_e$ and $\Lambda_c^+\rightarrow \Lambda(1405) e^+\nu_e$ is performed. The $\Lambda_c^+\rightarrow pK^-e^+\nu_e$ decay is observed with a significance of $8.2\sigma$ and the branching fraction is measured to be $\mathcal{B}(\Lambda_c^+\rightarrow pK^- e^+\nu_e)=(0.88\pm0.17_{\rm stat.}\pm0.07_{\rm syst.})\times 10^{-3}$. We also report evidence of $\Lambda_c^+\rightarrow \Lambda(1520)e^+\nu_e$ and $\Lambda_c^+\rightarrow \Lambda(1405)e^+\nu_e$ with significances of $3.3\sigma$ and $3.2\sigma$, respectively, and measure $\mathcal B(\Lambda^+_c\rightarrow \Lambda(1520)e^+\nu_e)=(1.02\pm0.52_{\rm stat.}\pm0.11_{\rm syst.})\times10^{-3}$ and $\mathcal B(\Lambda^+_c\rightarrow \Lambda(1405)[\rightarrow pK^-]e^+\nu_e)=(0.42\pm0.19_{\rm stat.}\pm0.04_{\rm syst.})\times10^{-3}$. Combining these with the inclusive semileptonic $\Lambda_c^+$ branching fraction measured by BESIII, the relative fraction is determined to be $[\mathcal{B}(\Lambda_c^+\rightarrow pK^-e^+\nu_e)/\mathcal{B}(\Lambda_c^+\rightarrow X e^+\nu_e)]=(2.1\pm0.4_{\rm stat.}\pm0.2_{\rm syst.})\%$, which provides a clear confirmation that semileptonic $\Lambda_c^+$ decays are not saturated by the $\Lambda \ell^+\nu_{\ell}$ final state.

Based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data taken at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we measure the branching fraction of $D^{*+}_s\to D^+_s\pi^0$ relative to that of $D^{*+}_s\to D^+_s\gamma$ to be $(6.16\pm 0.43\pm 0.19)\%$. The first uncertainty is statistical and the second one is systematic. By using the world average value of the branching fraction of $D^{*+}_s\to D^+_se^+e^-$, we determine the branching fractions of $D^{*+}_s\to D^+_s\gamma$ and $D^{*+}_s\to D^+_s\pi^0$ to be $(93.57\pm0.44\pm0.19)\%$ and $(5.76\pm0.44\pm0.19)\%$, respectively.

A bstract Using a sample of (10 . 09 ± 0 . 04) × 10 9 J/ψ decays collected with the BESIII detector, partial wave analyses of the decay $$ J/\psi \to \gamma {K}_S^0{K}_S^0{\pi}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> <mml:mo>→</mml:mo> <mml:mi>γ</mml:mi> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> are performed within the $$ {K}_S^0{K}_S^0{\pi}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> invariant mass region below 1.6 GeV/ c 2 . The covariant tensor amplitude method is used in both mass independent and mass dependent approaches. Both analysis approaches exhibit dominant pseudoscalar and axial vector components, and show good consistency for the other individual components. Furthermore, the mass dependent analysis reveals that the $$ {K}_S^0{K}_S^0{\pi}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> invariant mass spectrum for the pseudoscalar component can be well described with two isoscalar resonant states using relativistic Breit-Wigner model, i.e., the η (1405) with a mass of $$ 1391.7\pm {0.7}_{-0.3}^{+11.3} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>1391.7</mml:mn> <mml:mo>±</mml:mo> <mml:msubsup> <mml:mn>0.7</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>11.3</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> MeV/ c 2 and a width of $$ 60.8\pm {1.2}_{-12.0}^{+5.5} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>60.8</mml:mn> <mml:mo>±</mml:mo> <mml:msubsup> <mml:mn>1.2</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>12.0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>5.5</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> MeV, and the η (1475) with a mass of $$ 1507.6\pm {1.6}_{-32.2}^{+15.5} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>1507.6</mml:mn> <mml:mo>±</mml:mo> <mml:msubsup> <mml:mn>1.6</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>32.2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>15.5</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> MeV/ c 2 and a width of $$ 115.8\pm {2.4}_{-10.9}^{+14.8} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>115.8</mml:mn> <mml:mo>±</mml:mo> <mml:msubsup> <mml:mn>2.4</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>10.9</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>14.8</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> MeV. The first and second uncertainties are statistical and systematic, respectively. Alternate models for the pseudoscalar component are also tested, but the description of the $$ {K}_S^0{K}_S^0{\pi}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msup> <mml:mi>π</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> invariant mass spectrum deteriorates significantly.

We present a measurement of the dressed cross sections for $e^+ e^- \rightarrow \phi \eta^{\prime}$ at different center-of-mass energies between 3.508 and 4.600 GeV based on 15.1 fb$^{-1}$ of $e^+ e^-$ annihilation data collected with the BESIII detector operating at the BEPCII collider. In addition, a search for the decay $Y(4230) \to \phi \eta^{\prime}$ is performed. No clear signal is observed and the corresponding upper limit is provided.

Using 4.7 fb^{-1} of e^{+}e^{-} collision data at center-of-mass energies from 4.661 to 4.951 GeV collected by the BESIII detector at the BEPCII collider, we observe the X(3872) production process e^{+}e^{-}→ωX(3872) for the first time. The significance is 7.8σ, including both the statistical and systematic uncertainties. The e^{+}e^{-}→ωX(3872) Born cross section and the corresponding upper limit at 90% confidence level at each energy point are reported. The line shape of the cross section indicates that the ωX(3872) signals may be from the decays of some nontrivial structures.

A precision measurement of the matrix elements for η→π+π−π0 and η→π0π0π0 decays is performed using a sample of (10087±44)×106 J/ψ decays collected with the BESIII detector. The decay J/ψ→γη is used to select clean samples of 631,686 η→π+π−π0 decays and 272,322 η→π0π0π0 decays. The matrix elements for both channels are in reasonable agreement with previous measurements. The nonzero gX2Y term for the decay mode η→π+π−π0 is confirmed, as reported by the KLOE Collaboration, while the other higher-order terms are found to be insignificant. Dalitz plot asymmetries in the η→π+π−π0 decay are also explored and are found to be consistent with charge conjugation invariance. In addition, a cusp effect is investigated in the η→π0π0π0 decay, and no obvious structure around the π+π− mass threshold is observed.Received 16 February 2023Accepted 15 March 2023DOI:https://doi.org/10.1103/PhysRevD.107.092007Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHadronic decaysPhysical SystemsMesonsTechniquesLepton collidersParticles & Fields

Using (1.0087±0.0044)×10^{10} J/ψ events collected with the BESIII detector at the BEPCII storage ring, the process Ξ^{0}n→Ξ^{-}p is studied, where the Ξ^{0} baryon is produced in the process J/ψ→Ξ^{0}Ξ[over ¯]^{0} and the neutron is a component of the ^{9}Be, ^{12}C, and ^{197}Au nuclei in the beam pipe. A clear signal is observed with a statistical significance of 7.1σ. The cross section of the reaction Ξ^{0}+^{9}Be→Ξ^{-}+p+^{8}Be is determined to be σ(Ξ^{0}+^{9}Be→Ξ^{-}+p+^{8}Be)=(22.1±5.3_{stat}±4.5_{sys}) mb at the Ξ^{0} momentum of 0.818 GeV/c, where the first uncertainty is statistical and the second is systematic. No significant H-dibaryon signal is observed in the Ξ^{-}p final state. This is the first study of hyperon-nucleon interactions in electron-positron collisions and opens up a new direction for such research.

Using an $e^+e^-$ collision data sample of $(27.08 \pm 0.14) \times 10^{8}$ $\psi(3686)$ events collected by the BESIII detector, we report the first observation of $\chi_{cJ} \to \Omega^- \bar{\Omega}^+$ ($J=0,\,1,\,2$) decays with significances of $5.6\sigma$, $6.4\sigma$, and $18\sigma$, respectively, where the $\chi_{cJ}$ mesons are produced in the radiative $\psi(3686)$ decays. The branching fractions are determined to be $\mathcal{B}(\chi_{c0} \to \Omega^- \bar{\Omega}^+) = (3.51 \pm 0.54 \pm 0.29) \times 10^{-5}$, $\mathcal{B}(\chi_{c1} \to \Omega^- \bar{\Omega}^+) = (1.49 \pm 0.23 \pm 0.10) \times 10^{-5}$, and $\mathcal{B}(\chi_{c2} \to \Omega^- \bar{\Omega}^+) = (4.52 \pm 0.24 \pm 0.18) \times 10^{-5}$, where the first and second uncertainties are statistical and systematic, respectively.

The $\Xi^0$ asymmetry parameters are measured using entangled quantum $\Xi^0$-$\bar{\Xi}^0$ pairs from a sample of $(448.1 \pm 2.9) \times 10^6$ $\psi(3686)$ events collected with the BESIII detector at BEPCII. The relative phase between the transition amplitudes of the $\Xi^0 \bar{\Xi}^0$ helicity states is measured to be $\Delta \Phi = -0.050 \pm 0.150 \pm 0.020$~rad, which implies that there is no obvious polarization at the current level of statistics. The decay parameters of the $\Xi^0$ hyperon $(\alpha_{\Xi^0}, \alpha_{\bar{\Xi}^0}, \phi_{\Xi^0}, \phi_{\bar{\Xi}^0})$ and the angular distribution parameter $(\alpha_{\psi(3686)})$ and $\Delta \Phi$ are measured simultaneously for the first time. In addition, the $CP$ asymmetry observables are determined to be $A^{\Xi^0}_{CP} = (\alpha_{\Xi^0} + \alpha_{\bar{\Xi}^0})/(\alpha_{\Xi^0} - \alpha_{\bar{\Xi}^0})$ $= -0.007$ $\pm$ 0.082 $\pm$ 0.025 and $\Delta \phi^{\Xi^0}_{CP} = (\phi_{\Xi^0} + \phi_{\bar{\Xi}^0})/2$ $= -0.079$ $\pm$ 0.082 $\pm$ 0.010 rad, which are consistent with $CP$ conservation.

The study of the Cabibbo-favored semileptonic decay ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ is reported using $4.5\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ annihilation data collected at center-of-mass energies ranging from 4.600 to 4.699 GeV. The branching fraction of the decay is measured to be $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}})=(3.48\ifmmode\pm\else\textpm\fi{}0.1{4}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}0.1{0}_{\mathrm{syst}})%$, 3 times more precise than the prior world average result. Tests of lepton flavor universality using ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ ($\ensuremath{\ell}=e$, $\ensuremath{\mu}$) decays are reported for the first time, based on measurements of the differential decay rates and the forward-backward asymmetries in separate four-momentum transfer regions. The results are compatible with Standard Model predictions. Furthermore, we improve the determination of the form-factor parameters in ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ decays, which provide stringent tests and calibration for lattice quantum chromodynamics calculations.

A bstract Utilizing 7 . 33 fb − 1 of e + e − collision data taken at the center-of-mass energies of 4.128, 4.157, 4.178, 4.189, 4.199, 4.209, 4.219, and 4.226 GeV with the BESIII detector, the branching fraction of the leptonic decay $$ {D}_s^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> → τ + ν τ via τ + → μ + ν μ $$ \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> τ is measured to be $$ {\mathcal{B}}_{D_s^{+}\to {\tau}^{+}{\nu}_{\tau }} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>τ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msub> <mml:mi>ν</mml:mi> <mml:mi>τ</mml:mi> </mml:msub> </mml:mrow> </mml:msub> </mml:math> = (5 . 37 ± 0 . 17 stat ± 0 . 15 syst )%. Combining this branching fraction with the world averages of the measurements of the masses of τ + and $$ {D}_s^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> as well as the lifetime of $$ {D}_s^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> , we extract the product of the decay constant of $$ {D}_s^{+} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> and the c → s Cabibbo-Kobayashi-Maskawa matrix element to be $$ {f}_{D_s^{+}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>f</mml:mi> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:msub> </mml:math> |V cs | = (246 . 7 ± 3 . 9 stat ± 3 . 6 syst ) MeV. Taking |V cs | from a global fit in the standard model we obtain $$ {f}_{D_s^{+}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>f</mml:mi> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:msub> </mml:math> = (253 . 4 ± 4 . 0 stat ± 3 . 7 syst ) MeV. Conversely, taking $$ {f}_{D_s^{+}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>f</mml:mi> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> </mml:msub> </mml:math> from lattice quantum chromodynamics calculations, we obtain |V cs | = 0 . 987 ± 0 . 016 stat ± 0 . 014 syst .

Using a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider, a partial wave analysis on the decay $\gamma\gamma\phi$ is performed to investigate the intermediate resonances in $J/\psi\rightarrow\gamma X, X\rightarrow\gamma\phi$. The resonances $f_{1}(1285)$, $\eta(1405)$, $f_{1}(1420)$, $f_{1}(1510)$, $f_{2}(1525)$, $X(1835)$, $f_{2}(1950)$, $f_{2}(2010)$, $f_{0}(2200)$ and $\eta_{c}$ are observed with statistical significance greater than 5$\sigma$. The product branching fractions $\mathcal{B}(J/\psi\rightarrow\gamma X, X\rightarrow \gamma \phi)$ are reported. The resonance parameters of $\eta(1405)$ and $X(1835)$ are also measured.

The Born cross sections and effective form factors of the process e+e−→ΛΣ¯0+c.c. are measured at 14 center-of-mass energy points from 2.3094 to 3.0800 GeV, based on data corresponding to an integrated luminosity of (478.5±4.8) pb−1 collected with the BESIII detector. A nonzero Born cross section is observed at the center-of-mass energy of 2.3094 GeV with a statistical significance of more than five standard deviations, and the cross sections at other energies are obtained with improved precision compared to earlier measurements from the BABAR Collaboration. The Born cross-section line shape is described better by a shape considering the strong-interaction effects than by a pQCD motivated functional form.Received 8 August 2023Revised 27 October 2023Accepted 21 November 2023DOI:https://doi.org/10.1103/PhysRevD.109.012002Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasForm factorsParticle interactionsPhysical SystemsHyperonsParticles & Fields

In high-energy physics, precise measurements rely on highly reliable detector simulations. Traditionally, these simulations involve incorporating experiment data to model detector responses and fine-tuning them. However, due to the complexity of the experiment data, tuning the simulation can be challenging. One crucial aspect for charged particle identification is the measurement of energy deposition per unit length (referred to as dE/dx). This paper proposes a data-driven dE/dx simulation method using the Normalizing Flow technique, which can learn the dE/dx distribution directly from experiment data. By employing this method, not only can the need for manual tuning of the dE/dx simulation be eliminated, but also high-precision simulation can be achieved.

Using $(27.12 \pm 0.14) \times 10^{8}$ $\psi(3686)$ events collected with the BESIII detector at BEPCII, the decay of $\psi(3686) \to \Omega^- K^+ \bar{\Xi}^0 +c.c.$ is observed for the first time. The branching fraction of this decay is measured to be $\mathcal{B}_{\psi(3686) \to \Omega^- K^+ \bar{\Xi}^0 +c.c.}=(2.78 \pm 0.40 \pm 0.18 ) \times 10^{-6}$, where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.

Based on a data sample of 10 billion $J/\psi$ events collected with the BESIII detector, improved measurements of the Dalitz decays $\eta/\eta'\rightarrow\gamma e^+e^-$ are performed, where the $\eta$ and $\eta'$ are produced through the radiative decays $J/\psi\rightarrow\gamma \eta/\eta'$. The branching fractions of $\eta\rightarrow\gamma e^+e^-$ and $\eta'\rightarrow\gamma e^+e^-$ are measured to be $(7.07 \pm 0.05 \pm 0.23)\times10^{-3}$ and $(4.83\pm0.07\pm0.14)\times10^{-4}$, respectively. Within the single pole model, the parameter of electromagnetic transition form factor for $\eta\rightarrow\gamma e^+e^-$ is determined to be $\Lambda_{\eta}=(0.749 \pm 0.027 \pm 0.007)~ {\rm GeV}/c^{2}$. Within the multi-pole model, we extract the electromagnetic transition form factors for $\eta'\rightarrow\gamma e^+e^-$ to be $\Lambda_{\eta'} = (0.802 \pm 0.007\pm 0.008)~ {\rm GeV}/c^{2}$ and $\gamma_{\eta'} = (0.113\pm0.010\pm0.002)~ {\rm GeV}/c^{2}$. The results are consistent with both theoretical predictions and previous measurements. The characteristic sizes of the interaction regions for the $\eta$ and $\eta'$ are calculated to be $(0.645 \pm 0.023 \pm 0.007 )~ {\rm fm}$ and $(0.596 \pm 0.005 \pm 0.006)~ {\rm fm}$, respectively. In addition, we search for the dark photon in $\eta/\eta^\prime\rightarrow\gamma e^{+}e^{-}$, and the upper limits of the branching fractions as a function of the dark photon are given at 90\% confidence level.

Abstract In the melting process of non-ferrous metals, melt stirring is one of the most important processes. In this paper, a new type of EMS (Electromagnetic Stirring) device with long service life and low energy consumption is designed based on the basic equations of Maxwell electromagnetics combined with finite element method. The effect of the designed EMS on the non-ferrous metal melt is studied. The 3D numerical model of multi-field coupling of DC EMS device is established. The distribution and morphological characteristics of magnetic field and flow field are simulated by ANSYS software. Through the streamline distribution and the volume fraction cloud diagram analysis, it is found that the melt flow state and the Si composition distribution are different under different stirring speed especially for early time, but when the time is long enough, the melt will be stirred evenly. During the stirring, the alternating magnetic field can form the circumferential electromagnetic torque, through which the non-ferrous metal melt can move. It is found that the circulating flow inside the melt and the shear flow near the groove wall are in conflict with each other. This phenomenon creates favorable conditions for the collision, friction and mixing of non-ferrous metals and reinforcement groups.

With a data sample corresponding to an integrated luminosity of 11.5 fb−1 collected with the BESIII detector operating at the BEPCII storage ring, for the first time the light hadron decay χc1(3872)→π+π−η is searched for. While no significant signal is observed, the upper limits at the 90% confidence level for σ[e+e−→γχc1(3872)]B[χc1(3872)→π+π−η] at center of mass energies from 4.13 GeV to 4.34 GeV are determined. By normalizing to the χc1(3872)→π+π−J/ψ decay channel, a 90% confidence level upper limit for the branching fraction ratio R=B[χc1(3872)→π+π−η]/B[χc1(3872)→π+π−J/ψ]<0.12 is given. These measurements provide important inputs for understanding the internal structure of the χc1(3872) resonance.Received 26 August 2023Accepted 6 December 2023DOI:https://doi.org/10.1103/PhysRevD.109.L011102Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadronic decaysPhysical SystemsExotic mesonsParticles & FieldsNuclear Physics

With the data samples taken at center-of-mass energies from 2.00 to 3.08 GeV with the BESIII detector at the BEPCII collider, a partial wave analysis on the $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ process is performed. The Born cross sections for $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ and its intermediate processes $e^{+}e^{-}\rightarrow\rho\pi$ and $\rho(1450)\pi$ are measured as functions of $\sqrt{s}$. The results for $e^{+}e^{-}\rightarrow\pi^{+}\pi^{-}\pi^{0}$ are consistent with previous results measured with the initial state radiation method within one standard deviation, and improve the uncertainty by a factor of ten. By fitting the line shapes of the Born cross sections for the $e^{+}e^{-}\rightarrow\rho\pi$ and $\rho(1450)\pi$, a structure with mass $M = 2119\pm11\pm15\ {\rm MeV}/c^2$ and width $\Gamma=69\pm30\pm5 {\rm MeV}$ is observed with a significance of $5.9\sigma$, where the first uncertainties are statistical and the second ones are systematic. This structure can be intepreteted as an excited $\omega$ state.

A bstract Based on e + e − collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the process e + e − → $$ {K}_S^0{K}_L^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>L</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> π 0 . The results allow the Born cross sections of the process e + e − → $$ {K}_S^0{K}_L^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>L</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> π 0 , as well as its subprocesses e + e − → K ∗ (892) 0 $$ \overline{K} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> 0 and $$ {K}_2^{\ast } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mn>2</mml:mn> <mml:mo>∗</mml:mo> </mml:msubsup> </mml:math> (1430) 0 $$ \overline{K} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> 0 to be measured. The Born cross sections for e + e − → $$ {K}_S^0{K}_L^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mi>K</mml:mi> <mml:mi>L</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> π 0 are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process e + e − K ∗ (892) 0 $$ \overline{K} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> 0 is consistent with a vector meson state around 2.2 GeV with a significance of 3.2 σ . A Breit-Wigner fit determines its mass as M Y = (2164 . 7 ± 9 . 1 ± 3 . 1) MeV /c 2 and its width as Γ Y = (32 . 4 ± 21 . 0 ± 1 . 8) MeV.

We present the first observation of the singly Cabibbo-suppressed decay Λc+→ΛK+π0 with a significance of 5.7σ and the first evidence of Λc+→ΛK+π+π− decay with a significance of 3.1σ, based on e+e− annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to an integrated luminosity of 6.4 fb−1, in the center-of-mass energy range from 4.600 to 4.950 GeV. We determine the branching fractions of Λc+→ΛK+π0 and Λc+→ΛK+π+π− relative to their Cabibbo-favored counterparts to be B(Λc+→ΛK+π0)B(Λc+→Λπ+π0)=(2.09±0.39stat±0.07syst)×10−2 and B(Λc+→ΛK+π+π−)B(Λc+→Λπ+π+π−)=(1.13±0.41stat±0.06syst)×10−2, respectively. Moreover, by combining our measured result with the world average of B(Λc+→Λπ+π0), we obtain the branching fraction B(Λc+→ΛK+π0)=(1.49±0.27stat±0.05syst±0.08ref)×10−3. This result significantly departs from theoretical predictions based on quark SU(3) flavor symmetry, which is underpinned by the presumption of meson pair S-wave amplitude dominance.Received 21 November 2023Accepted 9 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.032003Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadronic decaysPhysical SystemsCharmed baryonsPropertiesFlavor symmetriesTechniquesLepton collidersParticles & Fields

With a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events accumulated with the BESIII detector, we analyze the decays $\eta'\rightarrow\pi^+\pi^-l^+l^-(l=e,$ $\mu)$ via the process $J/\psi\rightarrow\gamma\eta'$. The branching fractions are measured to be $\mathcal{B}(\eta'\rightarrow\pi^+\pi^-e^+e^-)=(2.45\pm0.02(\rm{stat.})\pm0.08(\rm{syst.})) \times10^{-3}$ and $\mathcal{B}(\eta'\rightarrow\pi^+\pi^-\mu^+\mu^-)=(2.16\pm0.12(\rm{stat.})\pm0.06(\rm{syst.}))\times10^{-5}$, and the ratio is $\frac{\mathcal{B}(\eta'\rightarrow\pi^{+}\pi^{-}e^{+}e^{-})}{\mathcal{B}(\eta'\rightarrow\pi^{+}\pi^{-}\mu^{+}\mu^{-})} = 113.4\pm0.9(\rm{stat.})\pm3.7(\rm{syst.})$. In addition, by combining the $\eta'\rightarrow\pi^+\pi^-e^+e^-$ and $\eta'\rightarrow\pi^+\pi^-\mu^+\mu^-$ decays, the slope parameter of the electromagnetic transition form factor is measured to be $b_{\eta'}=1.30\pm0.19\ (\mathrm{GeV}/c^{2})^{-2}$, which is consistent with previous measurements from BESIII and theoretical predictions from the VMD model. The asymmetry in the angle between the $\pi^+\pi^-$ and $l^+l^-$ decay planes, which has the potential to reveal the $CP$-violation originating from an unconventional electric dipole transition, is also investigated. The asymmetry parameters are determined to be $\mathcal{A}_{CP}(\eta'\rightarrow\pi^+\pi^-e^+e^-)=(-0.21\pm0.73(\rm{stat.})\pm0.01(\rm{syst.}))\%$ and $\mathcal{A}_{CP}(\eta'\rightarrow\pi^+\pi^-\mu^+\mu^-)=(0.62\pm4.71(\rm{stat.})\pm0.08(\rm{syst.}))\%$, implying that no evidence of $CP$-violation is observed at the present statistics. Finally, an axion-like particle is searched for via the decay $\eta'\rightarrow\pi^+\pi^-a, a\rightarrow e^+e^-$, and upper limits of the branching fractions are presented for the mass assumptions of the axion-like particle in the range of $0-500\ \mathrm{MeV}/c^{2}$.

Using data samples collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 3.80 to 4.95 GeV, corresponding to an integrated luminosity of 20 fb$^{-1}$, a measurement of Born cross sections for the $e^+e^-\to D^{0}\bar{D}^{0}$ and $D^{+}D^{-}$ processes is presented with unprecedented precision. By performing a simultaneous fit to the dressed cross sections for both processes, one possible new structure around 3.9 GeV/$c^2$ is observed for the first time, in addition to seven known resonances $\psi(3770)$, $\psi(4040)$, $\psi(4160)$, $Y(4230)$, $Y(4360)$, $\psi(4415)$, and $Y(4660)$. These results offer crucial experimental insights into the nature of hadron production in the open charm region.

A light scalar X0 or vector X1 particles have been introduced as a possible explanation for the (g−2)μ anomaly and dark matter phenomena. Using (8.998±0.039)×109 J/ψ events collected by the BESIII detector, we search for a light muon philic scalar X0 or vector X1 in the processes J/ψ→μ+μ−X0,1 with X0,1 invisible decays. No obvious signal is found, and the upper limits on the coupling g0,1′ between the muon and the X0,1 particles are set to be between 1.1×10−3 and 1.0×10−2 for the X0,1 mass in the range of 1<M(X0,1)<1000 MeV/c2 at 90% credibility level.Received 3 November 2023Revised 14 December 2023Accepted 25 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.L031102Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasAnomaliesExtensions of gauge sectorExtensions of scalar sectorParticle dark matterParticle decaysTechniquesLepton collidersParticles & Fields

Using a sample of 10 billion J/ψ events collected with the BESIII detector, the decays η′→π+π−π+π−, η′→π+π−π0π0 and η′→4π0 are studied via the process J/ψ→γη′. The branching fractions of η′→π+π−π+π− and η′→π+π−π0 π0 are measured to be (8.56±0.25(stat)±0.23(syst))×10−5 and (2.12±0.12(stat)±0.10(syst))×10−4, respectively, which are consistent with previous measurements but with improved precision. No significant η′→4π0 signal is observed, and the upper limit on the branching fraction of this decay is determined to be less than 1.24×10−5 at the 90% confidence level. In addition, an amplitude analysis of η′→π+π−π+π− is performed to extract the doubly virtual isovector form factor α for the first time. The measured value of α=1.22±0.33(stat)±0.04(syst), is in agreement with the prediction of the vector meson dominance model.Received 23 November 2023Accepted 23 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.032006Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsLight mesonsPropertiesForm factorsParticles & Fields

Current modeling methods of machine tool feed error are challenging to meet the demand of high-precision machining when facing complex machining conditions. To enhance the model’s predictive accuracy and the effectiveness of actual compensation, the Whale Particle Swarm Optimization (WPSO) algorithm is proposed to optimize the Backpropagation Neural Network (BPNN). Subsequently, the optimized network incorporates screw elongation and feed position as inputs to establish a feed-error prediction model. Ultimately, the established model was compared with other models and applied to real-time compensation experiments. The research results show that the proposed prediction model outperforms the BPNN model, the particle swarm-optimized BPNN model, and the whale-optimized BPNN model in various indicators. The accuracy of the prediction model was 93.12%, and the errors ranged from −3.80 μm to 4.57 μm with an average error of −0.30 μm. Under different operating conditions, the maximum backward and forward errors are reduced by 33.21% and 87.21%, and the average backward and forward errors are reduced by 57.15% and 84.37%, respectively. The error range is reduced by 67.41%. Beyond elevating prediction accuracy and compensation efficacy, the proposed model offers robust theoretical guidance for practical production.

Based on 7.33 fb−1 of e+e− collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, the experimental studies of the doubly Cabibbo-suppressed decays Ds+→K+K+π− and Ds+→K+K+π−π0 are reported. We determine the absolute branching fraction of Ds+→K+K+π− to be (1.24−0.26+0.28(stat)±0.06(syst))×10−4. No significant signal of Ds+→K+K+π−π0 is observed and the upper limit on its decay branching fraction at 90% confidence level is set to be 1.7×10−4.Received 24 October 2023Accepted 30 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.032011Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHadronic decaysPhysical SystemsCharm quarkCharmed mesonsParticles & Fields

The process e+e−→Σ+Σ¯− is studied from threshold up to 3.04 GeV/c2 via the initial-state radiation technique using data with an integrated luminosity of 12.0 fb−1, collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector at the BEPCII collider. The pair production cross sections and the effective form factors of Σ are measured in eleven Σ+Σ¯− invariant mass intervals from threshold to 3.04 GeV/c2. The results are consistent with the previous results from Belle and BESIII. Furthermore, the branching fractions of the decays J/ψ→Σ+Σ¯− and ψ(3686)→Σ+Σ¯− are determined and the obtained results are consistent with the previous results of BESIII.Received 3 January 2024Accepted 26 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.034029Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)PropertiesForm factorsParticles & Fields

Using $(2.712\pm0.014)\times 10^9$ $\psi(3686)$ events collected by the BESIII detector operating at the BEPCII collider, we report the first observation of $\psi(3686)\to 3\phi$ decay with a significance larger than 10$\sigma$. The branching fraction of this decay is determined to be $(1.46\pm0.05\pm0.17)\times10^{-5}$, where the first uncertainty is statistical and the second is systematic. No significant structure is observed in the $\phi\phi$ invariant mass spectra.

The Cabbibo-favored decay Λc+→Ξ0K+π0 is studied for the first time using 6.1 fb−1 of e+e− collision data at center-of-mass energies between 4.600 and 4.840 GeV, collected with the BESIII detector at the BEPCII collider. With a double-tag method, the branching fraction of the three-body decay Λc+→Ξ0K+π0 is measured to be (7.79±1.46±0.95)×10−3, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction of the two-body decay Λc+→Ξ(1530)0K+ is (5.99±1.04±0.32)×10−3, which is consistent with the previous result of (5.02±0.99±0.31)×10−3. In addition, the upper limit on the branching fraction of the doubly Cabbibo-suppressed decay Λc+→nK+π0 is 7.1×10−4 at the 90% confidence level. The upper limits on the branching fractions of Λc+→Σ0K+π0 and ΛK+π0 are also determined to be 1.8×10−3 and 2.0×10−3, respectively.1 MoreReceived 7 November 2023Accepted 23 January 2024DOI:https://doi.org/10.1103/PhysRevD.109.052001Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHadronic decaysPhysical SystemsCharmed baryonsParticles & Fields

Using (10087±44)×10^{6} J/ψ events collected with the BESIII detector, numerous Ξ^{-} and Λ decay asymmetry parameters are simultaneously determined from the process J/ψ→Ξ^{-}Ξ[over ¯]^{+}→Λ(pπ^{-})π^{-}Λ[over ¯](n[over ¯]π^{0})π^{+} and its charge-conjugate channel. The precisions of α_{Λ0} for Λ→nπ^{0} and α[over ¯]_{Λ0} for Λ[over ¯]→n[over ¯]π^{0} compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of Λ→nπ^{0} to that of Λ→pπ^{-}, ⟨α_{Λ0}⟩/⟨α_{Λ-}⟩, is determined to be 0.873±0.012_{-0.010}^{+0.011}, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than 5σ, which signifies the existence of the ΔI=3/2 transition in Λ for the first time. Besides, we test for CP symmetry in Ξ^{-}→Λπ^{-} and in Λ→nπ^{0} with the best precision to date.

Based on $(2712.4\pm14.1)\times10^{6}$ $\psi(3686)$ events collected with the BESIII detector, we study the decays $h_{c}\to3(\pi^{+}\pi^{-})\pi^{0}$, $h_{c}\to2(\pi^{+}\pi^{-})\omega$, $h_{c}\to2(\pi^{+}\pi^{-})\pi^{0}\eta$, $h_{c}\to2(\pi^{+}\pi^{-})\eta$, and $h_{c}\to p\bar{p}$ via $\psi(3686)\to\pi^{0}h_{c}$. The decay channel $h_{c}\to3(\pi^{+}\pi^{-})\pi^{0}$ is observed for the first time, and its branching fraction is determined to be $\left( {9.28\pm 1.14 \pm 0.77} \right) \times {10^{ - 3}}$, where the first uncertainty is statistical and the second is systematic. In addition, first evidence is found for the modes $h_{c} \to 2(\pi^{+}\pi^{-})\pi^{0}\eta$ and $h_{c}\to2(\pi^{+}\pi^{-})\omega$ with significances of 4.8$\sigma$ and 4.7$\sigma$, and their branching fractions are determined to be $(7.55\pm1.51\pm0.77)\times10^{-3}$ and $\left( {4.00 \pm 0.86 \pm 0.35}\right) \times {10^{ - 3}}$, respectively. No significant signals of $h_c\to 2(\pi^+\pi^-)\eta$ and $h_{c}\to p\bar{p}$ are observed, and the upper limits of the branching fractions of these decays are determined to be $<6.19\times10^{-4}$ and $<4.40\times10^{-5}$ at the 90% confidence level, respectively.

We report a first study of the semileptonic decay $D^0\rightarrow K^-\pi^0\mu^{+}\nu_{\mu}$ by analyzing an $e^+e^-$ annihilation data sample of $7.9~\mathrm{fb}^{-1}$ collected at the center-of-mass energy of 3.773 GeV with the BESIII detector. The absolute branching fraction of $D^0\to K^-\pi^0\mu^{+}\nu_{\mu}$ is measured for the first time to be $(0.729 \pm 0.014_{\rm stat} \pm 0.011_{\rm syst})\%$. Based on an amplitude analysis, the $S\text{-}{\rm wave}$ contribution is determined to be $(5.76 \pm 0.35_{\rm stat} \pm 0.29_{\rm syst})\%$ of the total decay rate in addition to the dominated $K^{*}(892)^-$ component. The branching fraction of $D^0\to K^{*}(892)^-\mu^+\nu_\mu$ is given to be $(2.062 \pm 0.039_{\rm stat} \pm 0.032_{\rm syst})\%$, which improves the precision of the world average by a factor of 5. Combining with the world average of ${\mathcal B}(D^0\to K^{*}(892)^-e^+\nu_e)$, the ratio of the branching fractions obtained is $\frac{{\mathcal B}(D^0\to K^{*}(892)^-\mu^+\nu_\mu)}{{\mathcal B}(D^0\to K^{*}(892)^-e^+\nu_e)} = 0.96\pm0.08$, in agreement with lepton flavor universality. Furthermore, assuming single-pole dominance parameterization, the most precise hadronic form factor ratios for $D^0\to K^{*}(892)^{-} \mu^+\nu_\mu$ are extracted to be $r_{V}=V(0)/A_1(0)=1.37 \pm 0.09_{\rm stat} \pm 0.03_{\rm syst}$ and $r_{2}=A_2(0)/A_1(0)=0.76 \pm 0.06_{\rm stat} \pm 0.02_{\rm syst}$.

Edition is aj ournalo ft he Gesellschaft Deutscher Chemiker (GDCh), the largest chemistryrelated scientific society in continental Europe.Information on the various activities and services of the GDCh, for example, cheaper subscription to Angewandte Chemie International Edition,aswell as applications for membership can be found at www.gdch.deor can be requested from GDCh, Postfach 900440, D-60444 Frankfurt am Main, Germany.…determines the product selectivity in the oxidative coupling of CH 4 as shown on the cover.In their Communication (e202319192), Guiyuan Jiang,E vgenii V. Kondratenko et al. describe how the formation of carbon oxides and ethane correlates with the binding strength of selective mono-atomic oxygen species.T he strength affects the probability of their recombination to diatomic oxygen species oxidizing methane to carbon oxides.Cover image credit:V ita A. Kondratenko.Photocatalysis Site-selective photocrosslinking of DNAduplex was achieved in the Research Article (e202319516) by Hiromu Kashida, Hiroyuki Asanuma et al.Aruthenium complex on atriplex-forming oligonucleotide effectively catalyzed [2+2] photocycloaddition of stilbene moieties under visible light.Bioorganic Chemistry Ar apid functional group transformation method that converts metabolic carboxylic acids into an ew ketone using the reagent 4-nitrophenyl-2H-azirine has been developed by Daniel Globisch et al. in their Communication (e202318579).

Based on 4.5 fb−1 of e+e− collision data accumulated at center-of-mass energies between 4599.53 and 4698.82 MeV with the BESIII detector, the decay Λc+→nKS0π+π0 is observed for the first time with a significance of 9.2σ. The branching fraction is measured to be (0.85±0.13±0.03)%, where the first uncertainty is statistical and the second is systematic, which differs from the theoretical prediction based on isospin by 4.4σ. This indicates that there may be resonant contributions or some unknown dynamics in this decay.Received 16 January 2024Accepted 6 March 2024DOI:https://doi.org/10.1103/PhysRevD.109.053005Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsBaryonsCharmed baryonsParticles & Fields

A massless particle beyond the Standard Model is searched for in the two-body decay Σ+→p+invisible using (1.0087±0.0044)×1010 J/ψ events collected at a center-of-mass energy of s=3.097GeV with the BESIII detector at the BEPCII collider. No significant signal is observed, and the upper limit on the branching fraction B(Σ+→p+invisible) is determined to be 3.2×10−5 at the 90% confidence level. This is the first search for a flavor-changing neutral current process with missing energy in hyperon decays which plays an important role in constraining new physics models.

By analyzing $e^+e^-$ annihilation data corresponding to an integrated luminosity of 2.93 $\rm fb^{-1}$ collected at a center-of-mass energy of 3.773 GeV with the \text{BESIII} detector, the first observation of the semileptonic decays $D^0\rightarrow K_S^0\pi^-\pi^0 e^+ \nu_e$ and $D^+\rightarrow K_S^0\pi^+\pi^- e^+ \nu_e$ is reported. With a dominant hadronic contribution from $K_1(1270)$, the branching fractions are measured to be $\mathcal{B}(D^0\rightarrow {K}_1(1270)^-(\to K^0_S\pi^-\pi^0)e^+\nu_e)=(1.69^{+0.53}_{-0.46}\pm0.15)\times10^{-4}$ and $\mathcal{B}(D^+\to \bar{K}_1(1270)^0(\to K^0_S\pi^+\pi^-)e^+\nu_e)=(1.47^{+0.45}_{-0.40}\pm0.20)\times10^{-4}$ with statistical significance of 5.4$\sigma$ and 5.6$\sigma$, respectively. When combined with measurements of the $K_1(1270)\to K^+\pi^-\pi$ decays, the absolute branching fractions are determined to be $\mathcal{B}(D^0\to K_1(1270)^-e^+\nu_e)=(1.05^{+0.33}_{-0.28}\pm0.12\pm0.12)\times10^{-3}$ and $\mathcal{B}(D^+\to \bar{K}_1(1270)^0e^+\nu_e)=(1.29^{+0.40}_{-0.35}\pm0.18\pm0.15)\times10^{-3}$. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainties originate from the assumed branching fractions of the $K_1(1270)\to K\pi\pi$ decays.

Based on a data sample of 10 billion J/ψ events collected with the BESIII detector, improved measurements of the Dalitz decays η/η′→γe+e− are performed, where the η and η′ are produced through the radiative decays J/ψ→γη/η′. The branching fractions of η→γe+e− and η′→γe+e− are measured to be (7.07±0.05±0.23)×10−3 and (4.83±0.07±0.14)×10−4, respectively. Within the single-pole model, the parameter of electromagnetic transition form factor for η→γe+e− is determined to be Λη=(0.749±0.027±0.007) GeV/c2. Within the multipole model, we extract the electromagnetic transition form factors for η′→γe+e− to be Λη′=(0.802±0.007±0.008) GeV/c2 and γη′=(0.113±0.010±0.002) GeV/c2. The results are consistent with both theoretical predictions and previous measurements. The characteristic sizes of the interaction regions for the η and η′ are calculated to be (0.645±0.023±0.007) fm and (0.596±0.005±0.006) fm, respectively. In addition, we search for the dark photon in η/η′→γe+e−, and the upper limits of the branching fractions as a function of the dark photon are given at 90% confidence level.1 MoreReceived 17 January 2024Accepted 14 March 2024DOI:https://doi.org/10.1103/PhysRevD.109.072001Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDark matterForm factorsPhysical SystemsElectronsLight mesonsParticles & Fields

Six $C$-even states, denoted as $X$, with quantum numbers $J^{PC}=0^{-+}$, $1^{\pm+}$, or $2^{\pm+}$, are searched for via the $e^+e^-\to\gamma D_{s}^{\pm}D_{s}^{*\mp}$ process using $(1667.39\pm8.84)~\mathrm{pb}^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energy of $\sqrt{s}=(4681.92\pm0.30)~\mathrm{MeV}$. No statistically significant signal is observed in the mass range from $4.08$ to $4.32~\mathrm{GeV}/c^{2}$. The upper limits of $\sigma[e^+e^-\to\gamma X]\cdot \mathcal{B}[X \to D_{s}^{\pm}D_{s}^{*\mp}]$ at a $90\%$ confidence level are determined.

ν e , using 7.9 fb -1 of e þ e -annihilation data collected at the center-of-mass energy ffiffi ffi s p ¼ 3.773GeV by the BESIII detector operating at the BEPCII collider.No significant signals are observed, and upper limits are set at the 90% confidence level of 2.13 × 10 -5 , 1.54 × 10 -5 , and 2.10 × 10 -5 for the branching fractions of D 0 → K 0 S K -e þ ν e , D þ → K 0

A bstract Using (27 . 12 ± 0 . 14) × 10 8 ψ (3686) events collected with the BESIII detector at BEPCII, the decay of ψ (3686) → $$ {\varOmega}^{-}{K}^{+}{\overline{\Xi}}^0 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>Ω</mml:mi> <mml:mo>−</mml:mo> </mml:msup> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mover> <mml:mi>Ξ</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> </mml:msup> </mml:math> + c . c . is observed for the first time. The branching fraction of this decay is measured to be $$ {\mathcal{B}}_{\psi (3686)\to {\varOmega}^{-}{K}^{+}{\overline{\Xi}}^0+\textrm{c}.\textrm{c}.} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi>ψ</mml:mi> <mml:mfenced> <mml:mn>3686</mml:mn> </mml:mfenced> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>Ω</mml:mi> <mml:mo>−</mml:mo> </mml:msup> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mover> <mml:mi>Ξ</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mn>0</mml:mn> </mml:msup> <mml:mo>+</mml:mo> <mml:mi>c</mml:mi> <mml:mo>.</mml:mo> <mml:mi>c</mml:mi> <mml:mo>.</mml:mo> </mml:mrow> </mml:msub> </mml:math> = (2 . 78 ± 0 . 40 ± 0 . 18) × 10 − 6 , where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.

Using e^{+}e^{-} collision data corresponding to an integrated luminosity of 7.33 fb^{-1} recorded by the BESIII detector at center-of-mass energies between 4.128 and 4.226 GeV, we present an analysis of the decay D_{s}^{+}→π^{+}π^{-}e^{+}ν_{e}, where the D_{s}^{+} is produced via the process e^{+}e^{-}→D_{s}^{*±}D_{s}^{∓}. We observe the f_{0}(980) in the π^{+}π^{-} system and the branching fraction of the decay D_{s}^{+}→f_{0}(980)e^{+}ν_{e} with f_{0}(980)→π^{+}π^{-} measured to be (1.72±0.13_{stat}±0.10_{syst})×10^{-3}, where the uncertainties are statistical and systematic, respectively. The dynamics of the D_{s}^{+}→f_{0}(980)e^{+}ν_{e} decay are studied with the simple pole parametrization of the hadronic form factor and the Flatté formula describing the f_{0}(980) in the differential decay rate, and the product of the form factor f_{+}^{f_{0}}(0) and the c→s Cabibbo-Kobayashi-Maskawa matrix element |V_{cs}| is determined for the first time to be f_{+}^{f_{0}}(0)|V_{cs}|=0.504±0.017_{stat}±0.035_{syst}. Furthermore, the decay D_{s}^{+}→f_{0}(500)e^{+}ν_{e} is searched for the first time but no signal is found. The upper limit on the branching fraction of D_{s}^{+}→f_{0}(500)e^{+}ν_{e}, f_{0}(500)→π^{+}π^{-} decay is set to be 3.3×10^{-4} at 90% confidence level.

Based on $(2.712\pm0.014)\times10^9$ $\psi(3686)$ events collected by the BESIII collaboration, evidence of the hadronic decay $h_c\to K_S^0K^+\pi^-+c.c.$ is found with a significance of $4.3\sigma$ in the $\psi(3686)\to\pi^0 h_c$ process. The branching fraction of $h_c\to K_S^0 K^+\pi^- +c.c.$ is measured to be $(7.3\pm0.8\pm1.8)\times10^{-4}$, where the first and second uncertainties are statistical and systematic, respectively. Combining with the exclusive decay width of $\eta_c\to K\bar{K}\pi$, our result indicates inconsistencies with both pQCD and NRQCD predictions.

Search for the decay χ c1 ð3872Þ → π + π -χ c1 M. Ablikim et al.

We search for the di-photon decay of a light pseudoscalar axion-like particle, $a$, in radiative decays of the $J/\psi$, using 10 billion $J/\psi$ events collected with the BESIII detector. We find no evidence of a narrow resonance and set upper limits at the $95\%$ confidence level on the product branching fraction $\mathcal{B}(J/\psi \to \gamma a) \times \mathcal{B}(a \to \gamma \gamma)$ and the axion-like particle photon coupling constant $g_{a \gamma \gamma}$ in the ranges of $(3.6-49.8) \times 10^{-8}$ and $(2.2 -103.8)\times 10^{-4}$ GeV$^{-1}$, respectively, for $0.18 \le m_a \le 2.85~$ GeV/$c^2$. These are the most stringent limits to date in this mass region.

We search for the hadronic decay $\eta_c(2S)\to 2(\pi^+\pi^-)$ in the $\psi(3686)\to\gamma\eta_c(2S)$ radiative decay using $(27.12\pm 0.14)\times 10^8$ $\psi(3686)$ events collected by the BESIII detector at the BEPCII collider. No significant signal is found, and the upper limit of $\mathcal{B}[\psi(3686)\to\gamma\eta_c(2S)]\mathcal{B}[\eta_c(2S)\to 2(\pi^+\pi^-)]$ is determined to be $0.78\times 10^{-6}$ at the 90\% confidence level. Using $\psi(3686)\to\gamma\chi_{cJ}$ transitions, we also measure the branching fractions of $\mathcal{B}[\chi_{cJ(J=0,1,2)}\to 2(\pi^+\pi^-)]$, which are $\mathcal{B}[\chi_{c0}\to 2(\pi^+\pi^-)]=(2.127\pm 0.002~(\mathrm{stat.})\pm 0.101~(\mathrm{syst.}))$\%, $\mathcal{B}[\chi_{c1}\to 2(\pi^+\pi^-)]=(0.685\pm 0.001~(\mathrm{stat.})\pm 0.031~\mathrm{syst.}))$\%, and $\mathcal{B}[\chi_{c2}\to 2(\pi^+\pi^-)]=(1.153\pm 0.001~(\mathrm{stat.})\pm 0.063~(\mathrm{syst.}))$\%.

The Born cross sections for the process $e^{+}e^{-}\to \omega\eta^{\prime}$ are measured at 22 center-of-mass energies from 2.000 to 3.080 GeV using data collected with the BESIII detector at the BEPCII collider. A resonant structure is observed with a statistical significance of 9.6$\sigma$. A Breit-Wigner fit determines its mass to be $M_R=(2153\pm30\pm31)~{\rm{MeV}}/c^{2}$ and its width to be $\Gamma_{R}=(167\pm77\pm7)~\rm{MeV}$, where the first uncertainties are statistical and the second are systematic.

Based on 4.5 fb−1 of e+e− collision data accumulated at center-of-mass energies between 4599.53 and 4698.82 MeV with the BESIII detector, we measure the absolute branching fraction of the Cabibbo-favored decay Λc+→nKS0π+ with the precision improved by a factor of 2.8 and report the first evidence for the singly-Cabibbo-suppressed decay Λc+→nKS0K+. The branching fractions for Λc+→nKS0π+ and Λc+→nKS0K+ are determined to be (1.86±0.08±0.04)×10−2 and (3.9−1.4+1.7±0.3)×10−4, respectively, where the first uncertainties are statistical and the second ones are systematic.Received 30 November 2023Accepted 23 February 2024DOI:https://doi.org/10.1103/PhysRevD.109.072010Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionHadronic decaysPhysical SystemsCharmed baryonsNeutronsTechniquesLepton collidersAccelerators & BeamsParticles & FieldsStatistical Physics & ThermodynamicsNuclear Physics

Based on a sample of (448.1±2.9)×106 ψ(3686) events collected with the BESIII detector at BEPCII, the decays of ψ(3686)→K−ΛΞ¯++c.c. with Ξ¯+→Λ¯π+, Λ¯→p¯π+ are studied. We investigate the two excited resonances, Ξ(1690)− and Ξ(1820)−, which are each observed with large significance (≫10σ) in the K−Λ invariant mass distributions. A partial wave analysis is performed, and the spin-parities of Ξ(1690)− and Ξ(1820)− are measured to be 12− and 32−, respectively. The masses, widths, and product branching fractions of Ξ(1690)− and Ξ(1820)− are also measured.Received 30 August 2023Accepted 29 February 2024DOI:https://doi.org/10.1103/PhysRevD.109.072008Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle decaysParticle interactionsParticle productionAtomic, Molecular & OpticalAccelerators & BeamsParticles & Fields

We report the first amplitude analysis of the decays $D^{0} \to \pi^{+} \pi^{-} \eta$ and $D^{+} \rightarrow \pi^{+}\pi^{0}\eta$ using a data sample taken with the BESIII detector at the center-of-mass energy of 3.773 GeV, corresponding to an integrated luminosity of 7.9 ${\rm fb}^{-1}$. The contribution from the process $D^{0(+)} \to a_{0}(980)^{+} \pi^{-(0)}$ is significantly larger than the $D^{0(+)} \to a_{0}(980)^{-(0)} \pi^{+}$ contribution. The ratios $\mathcal{B}(D^{0} \rightarrow a_{0}(980)^{+}\pi^{-})/\mathcal{B}(D^{0} \rightarrow a_{0}(980)^{-}\pi^{+})$ and $\mathcal{B}(D^{+} \rightarrow a_{0}(980)^{+}\pi^{0})/\mathcal{B}(D^{+} \rightarrow a_{0}(980)^{0}\pi^{+})$ are measured to be $7.5^{+2.5}_{-0.8\,\mathrm{stat.}}\pm1.7_{\mathrm{syst.}}$ and $2.6\pm0.6_{\mathrm{stat.}}\pm0.3_{\mathrm{syst.}}$, respectively. The measured $D^{0}$ ratio disagrees with the theoretical predictions by orders of magnitudes, thus implying a substantial contribution from final-state interactions.

We present measurements of the Born cross sections for the processes e^{+}e^{-}→ωχ_{c1} and ωχ_{c2} at center-of-mass energies sqrt[s] from 4.308 to 4.951 GeV. The measurements are performed with data samples corresponding to an integrated luminosity of 11.0 fb^{-1} collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring. Assuming the e^{+}e^{-}→ωχ_{c2} signals come from a single resonance, the mass and width are determined to be M=(4413.6±9.0±0.8) MeV/c^{2} and Γ=(110.5±15.0±2.9) MeV, respectively, which is consistent with the parameters of the well-established resonance ψ(4415). In addition, we also use one single resonance to describe the e^{+}e^{-}→ωχ_{c1} line shape and determine the mass and width to be M=(4544.2±18.7±1.7) MeV/c^{2} and Γ=(116.1±33.5±1.7) MeV, respectively. The structure of this line shape, observed for the first time, requires further understanding.

Using (2.712±0.014)×109 ψ(3686) events collected by the BESIII detector operating at the BEPCII collider, we report the first observation of ψ(3686)→3ϕ decay with a significance larger than 10σ. The branching fraction of this decay is determined to be (1.46±0.05±0.17)×10−5, where the first uncertainty is statistical and the second is systematic. No significant structure is observed in the ϕϕ invariant mass spectra.Received 4 March 2024Accepted 3 April 2024DOI:https://doi.org/10.1103/PhysRevD.109.072015Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionPhysical SystemsCharm quarkParticles & Fields

Using e+e− collision data collected with the BESIII detector operating at the BEPCII collider, the Born cross sections of e+e−→Λc+Λ¯c(2595)−+c.c. and e+e−→Λc+Λ¯c(2625)−+c.c. are measured for the first time at center-of-mass energies of s=4918.0 and 4950.9 MeV. Nonzero cross sections are observed very close to the production threshold. The measured Born cross sections of e+e−→Λc+Λ¯c(2625)−+c.c. are about 2–3 times greater than those of e+e−→Λc+Λ¯c(2595)−+c.c., providing the similar behavior as semileptonic decays of Λb0, but different behavior from that in the hadronic decays of Λb0. The Born cross sections are 15.6±3.1±0.9 pb and 29.4±3.7±2.7 pb for e+e−→Λc+Λ¯c(2595)−+c.c., and are 43.4±4.0±4.1 pb and 76.8±6.5±4.2 pb for e+e−→Λc+Λ¯c(2625)−+c.c. at s=4918.0 and 4950.9 MeV, respectively. Based on the polar angle distributions of the Λ¯c(2625)− and Λc(2625)+, the form-factor ratios |GE|2+3|GM|2/|GC| are determined for e+e−→Λc+Λ¯c(2625)−+c.c. for the first time, which are 5.95±4.07±0.15 and 0.94±0.32±0.02 at s=4918.0 and 4950.9 MeV, respectively. All of these first uncertainties are statistical and second systematic.Received 15 December 2023Accepted 2 April 2024DOI:https://doi.org/10.1103/PhysRevD.109.L071104Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasStrong interactionPhysical SystemsBaryonsCharm quarkCharmed baryonsExotic baryonsPropertiesForm factorsParticles & Fields

Detector studies for future experiments rely on advanced software tools to estimate performance and optimize their design and technology choices. The Key4hep project provides a flexible turnkey solution for the full experiment life-cycle based on established community tools such as ROOT, Geant4, DD4hep, Gaudi, podio and spack. Members of the CEPC, CLIC, EIC, FCC, and ILC communities have joined to develop this framework and have merged, or are in the progress of merging, their respective software environments into the Key4hep stack. These proceedings will give an overview over the recent progress in the Key4hep project: covering the developments towards adaptation of state-of-theart tools for simulation (DD4hep, Gaussino), track and calorimeter reconstruction (ACTS, CLUE), particle flow (PandoraPFA), analysis via RDataFrame, and visualization with Phoenix, as well as tools for testing and validation.

The Circular Electron Positron Collider (CEPC) is a future experiment aimed at studying the properties of the Higgs boson with high precision. This requires excellent track reconstruction and particle identification (PID) performance, which is achieved in the 4 th conceptual detector design of the CEPC experiments by combining a silicon tracker and a drift chamber. The drift chamber not only improves track reconstruction but also provides excellent PID with the cluster counting method. To evaluate the performance of this design accurately, a detailed simulation is necessary. In this paper, we present a refined drift chamber simulation by combining Geant4 and Garfield++. However, traditional waveform simulation using Garfield++ is extremely time-consuming, which motivates us to develop a fast waveform simulation method using a neural network. We validate the method using real data from the BESIII experiment. The results demonstrate the effectiveness of our approach and provide valuable insights for future experiments.

The Jiangmen Underground Neutrino Observatory (JUNO) experiment is set to begin data taking in 2024 with the aim of determining the neutrino mass ordering (NMO) to a significance of 3 σ after 6 years of data taking. Achieving this goal requires effective background suppression, with the background induced by cosmic-ray muons being one of the most significant sources of interference in the NMO study. Accurately simulating the cosmic-ray muon background is crucial for the success of the experiment, but the sheer number of optical photons produced by the muon makes this detector simulation process extremely time-consuming using traditional methods such as Geant4. This paper presents a fast muon simulation method that employs neural networks to expedite the simulation process. Our approach achieves an order-of-magnitude speed-up in simulation time compared to Geant4, while still producing accurate results.

Fault detection is a research topic attracting much attention in IIoT. However, the continuous accumulation and growth of IIoT data leads to the catastrophic forgetting problem in the fault detection model and data heterogeneity, which creates a bottleneck for the performance and generalization of federated learning in fault detection. To improve the fault detection performance of federated learning models in data incremental scenarios, we propose a federatedincremental-learning-based fault detection method for IIoT, namely FIL-CAD. Firstly, comparing the knowledge distillation, the accuracies of different data classes in the global and local models are chosen as the model lightweight learning features, and the loss function is weighted. Secondly, we introduce the concept of data learning depth. It computes different model weights in the aggregation based on their degrees of data sample learning and model training participation and obtains the global model through weighted aggregation. Additionally, FIL-CAD supports the combination of differential privacy to protect data privacy. The proposed method is compared with four benchmark methods on four datasets, which include CWRU and MFPT bearing datasets. Then, the experimental results show that FIL-CAD performs optimally in accuracy and F1-Score, and the average accuracy is improved by 1.32%-18.52%, demonstrating the superiority of FIL-CAD.

Using data samples collected with the BESIII detector operating at the BEPCII storage ring, we measure the cross sections of the e+e−→π+π−D+D− process at center-of-mass energies from 4.190 to 4.946 GeV with a partial reconstruction method. Resonance structures are seen and the cross section line shape can be described by the coherent sum of either two Breit-Wigner functions or a Breit-Wigner function and a phase space term. The mass and width of the resonance at about 4.4 GeV are determined to be (4371.6±2.5±9.2) MeV/c2 and (167±4±29) MeV, respectively, which are in agreement with those of the ψ(4360) or Y(4390) state. The spin-3D-wave charmonium state X(3842) is searched for through the e+e−→π+π−X(3842)→π+π−D+D− process, and evidence with a significance of 4.2σ is found in the data samples with center-of-mass energies from 4.6 to 4.7 GeV.2 MoreReceived 29 July 2022Accepted 12 September 2022DOI:https://doi.org/10.1103/PhysRevD.106.052012Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Hadronic decaysResearch AreasParticle phenomenaParticle decaysHadronic decaysResearch AreasHadronic decaysParticle decaysParticle phenomenaParticles & Fields

We report a branching fraction measurement of the singly Cabibbo-suppressed decay $\Lambda_{c}^{+}\to\Lambda K^{+}$ using a data sample collected with the BESIII detector at the BEPCII storage ring. The data span center-of-mass energies from 4.599 to 4.950 GeV and correspond to an integrated luminosity of 6.44 fb$^{-1}$. The branching fraction of $\Lambda_{c}^{+}\to\Lambda K^{+}$ relative to that of the Cabibbo-favored decay $\Lambda_{c}^{+}\to\Lambda \pi^{+}$ is measured to be $\mathcal{R}=\frac{\mathcal{B}(\Lambda_{c}^{+}\to\Lambda K^{+})}{\mathcal{B}(\Lambda_{c}^{+}\to\Lambda \pi^{+})}=(4.78\pm0.34\pm0.20)\%$. Combining with the world-average value of $\mathcal{B}(\Lambda_{c}^{+}\to\Lambda \pi^{+})$, we obtain $\mathcal{B}(\Lambda_c^+\to\Lambda K^+)=(6.21\pm0.44\pm0.26\pm0.34)\times 10^{-4}$. Here the first uncertainties are statistical, the second systematic, and the third comes from the uncertainty of the $\Lambda_{c}^{+}\to\Lambda \pi^{+}$ branching fraction. This result, which is more precise than previous measurements, does not agree with theoretical predictions, and suggests that non-factorizable contributions have been under-estimated in current models.

A study group was formed in Beijing in September 2013 to investigate the feasibility of a high energy Circular Electron Positron Collider (CEPC) as a Higgs and/or Z factory, and a subsequent Super proton-proton Collider (SPPC). A provisional organization structure and a management team, consisted mostly of Chinese physicists, were established to guide the initial study [1]. The group aims at establishing an international collaboration on CEPC-SPPC after sufficient progress has been made in China or it has been given government funding for RD Volume 2 describes the CEPC accelerator design and SPPC consideration, and the associated civil engineering [2]. The contents presented are preliminary and are predominately focused on the CEPC. Formal CDR and TDR work will follow.

The hadronic decay ηc(2S)→3(π+π−) is observed with a statistical significance of 9.3 standard deviations using (448.1±2.9)×106 ψ(3686) events collected by the BESIII detector at the BEPCII collider. The measured mass and width of ηc(2S) are (3643.4±2.3 (stat)±4.4 (syst)) MeV/c2 and (19.8±3.9 (stat)±3.1 (syst)) MeV, respectively, which are consistent with the world average values within two standard deviations. The product branching fraction B[ψ(3686)→γηc(2S)]×B[ηc(2S)→3(π+π−)] is measured to be (9.2±1.0 (stat)±1.2 (syst))×10−6. Using B[ψ(3686)→γηc(2S)]=(7.0+3.4−2.5)×10−4, we obtain B[ηc(2S)→3(π+π−)]=(1.31±0.15 (stat)±0.17 (syst) (+0.64−0.47) (extr))×10−2, where the third uncertainty is from B[ψ(3686)→γηc(2S)]. We also measure the χcJ→3(π+π−) (J=0, 1, 2) decays via ψ′→γχcJ transitions. The branching fractions are B[χc0→3(π+π−)]=(2.080±0.006 (stat)±0.068 (syst))×10−2, B[χc1→3(π+π−)]=(1.092±0.004 (stat)±0.035 (syst))×10−2, and B[χc2→3(π+π−)]=(1.565±0.005 (stat)±0.048 (syst))×10−2.Received 19 June 2022Accepted 28 July 2022DOI:https://doi.org/10.1103/PhysRevD.106.032014Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasStrong interactionPhysical SystemsQuarkoniaTechniquesParticle data analysisParticles & Fields

Based on a sample of $4.\text{5 }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ annihilation data collected in the energy region between 4.6 GeV and 4.7 GeV with the BESIII detector at BEPCII, two singly Cabibbo-suppressed decays ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{K}^{+}$ and ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0}$ are studied. The ratio of the branching fraction $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{K}^{+})$ relative to $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{\ensuremath{\pi}}^{+})$ is measured to be $0.0361\ifmmode\pm\else\textpm\fi{}0.0073(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.0005(\mathrm{syst}.)$, and the ratio of $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0})$ relative to $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ is measured to be $0.0106\ifmmode\pm\else\textpm\fi{}0.0031(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.0004(\mathrm{syst}.)$. After taking the world-average branching fractions of the reference decay channels, the branching fractions $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{K}^{+})$ and $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0})$ are determined to be $(4.7\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.1(\mathrm{syst}.)\ifmmode\pm\else\textpm\fi{}0.3(\mathrm{ref}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $(4.8\ifmmode\pm\else\textpm\fi{}1.4(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2(\mathrm{syst}.)\ifmmode\pm\else\textpm\fi{}0.3(\mathrm{ref}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, respectively. The branching fraction of the ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0}$ decay is measured for the first time.

A search for supersymmetry in hadronic final states with highly boosted W bosons and b jets is presented, focusing on compressed scenarios. The search is performed using proton-proton collision data at a center-of-mass energy of 8 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.7 inverse femtobarns. Events containing candidates for hadronic decays of boosted W bosons are identified using jet substructure techniques, and are analyzed using the razor variables M[R] and R^2, which characterize a possible signal as a peak on a smoothly falling background. The observed event yields in the signal regions are found to be consistent with the expected contributions from standard model processes, which are predicted using control samples in the data. The results are interpreted in terms of gluino-pair production followed by their exclusive decay into top squarks and top quarks. The analysis excludes gluino masses up to 1.1 TeV for light top squarks decaying solely to a charm quark and a neutralino, and up to 700 GeV for heavier top squarks decaying solely to a top quark and a neutralino.

Detector optimisation and physics performance studies are an integral part of the development of future collider experiments. The Key4hep project aims to design a common set of software tools for future, or even present, High Energy Physics projects. The proceeding describes the main components that are developed as part of Key4hep: the event data model EDM4hep, simulation interfaces to Delphes and Geant4, the k4MarlinWrapper to integrate iLCSoft components, as well as build and validation tools to ensure functionality and compatibility among the components. They also include the different adaptation processes by the CEPC, CLIC, FCC, and ILC communities towards this project, which show that Key4hep is a viable long term solution as baseline software for high energy experiments.

The cross section of the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ is measured at nineteen center-of-mass energies from 2.0 to 3.08 GeV using data collected with the BESIII detector at the BEPCII storage ring. A resonant structure around 2.20 GeV is observed with statistical significance larger than $5\ensuremath{\sigma}$. Using a coherent fit to the cross section line shape, the mass and width are determined to be $M=2222\ifmmode\pm\else\textpm\fi{}7\ifmmode\pm\else\textpm\fi{}2\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and $\mathrm{\ensuremath{\Gamma}}=59\ifmmode\pm\else\textpm\fi{}30\ifmmode\pm\else\textpm\fi{}6\text{ }\text{ }\mathrm{MeV}$, respectively, where the first uncertainties are statistical and the second ones are systematic.

We present a search for the lepton flavor violating decay J/ψ → e±μ∓ using 8.998 × 109J/ψ events collected with the BESIII detector at the BEPCII e+e− storage ring. No excess of signal above background is observed; we therefore set an upper limit on the branching fraction of $${\cal B}\left( {J/\psi \to {e^ \pm }{\mu ^ \mp }} \right) < \,4.5 \times {10^{ - 9}}$$ at the 90% confidence level. Improving the previous best result by a factor of more than 30, this measurement places the most stringent limit to date on lepton flavor violation in the heavy quarkonium sector.