Y. Chào

We report the first observation of a narrow charmmonium state produced in the exclusive decay process B+->K+ pi+pi- J/psi. This state, which decays into pi+pi-J/psi, has a mass of 3871.8+-0.7(stat)+-0.4(syst) MeV, which is very near the M_D + M_D* mass threshold. The results are based on an analysis of 152M BBbar events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider.

We present a measurement of the standard model CP violation parameter sin2φ1 based on a 29.1fb−1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. One neutral B meson is fully reconstructed as a J/ψKS, ψ(2S)KS, χc1KS, ηcKS, J/ψKL, or J/ψK*0 decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2φ1=0.99±0.14(stat)±0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.Received 18 July 2001DOI:https://doi.org/10.1103/PhysRevLett.87.091802©2001 American Physical Society

A distinct peak is observed in the ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}$ invariant mass distribution near 4.43 GeV in $B\ensuremath{\rightarrow}K{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}$ decays. A fit using a Breit-Wigner resonance shape yields a peak mass and width of $M=4433\ifmmode\pm\else\textpm\fi{}4(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}$ and $\ensuremath{\Gamma}={45}_{\ensuremath{-}13}^{+18}(\mathrm{stat}{)}_{\ensuremath{-}13}^{+30}(\mathrm{syst})\text{ }\text{ }\mathrm{MeV}$. The product branching fraction is determined to be $\mathcal{B}\mathbf{(}{B}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{\mp}}{Z}^{\ifmmode\pm\else\textpm\fi{}}(4430)\mathbf{)}\ifmmode\times\else\texttimes\fi{}\mathcal{B}\mathbf{(}{Z}^{\ifmmode\pm\else\textpm\fi{}}(4430)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\psi}}^{\ensuremath{'}}\mathbf{)}=(4.1\ifmmode\pm\else\textpm\fi{}1.0(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.4(\mathrm{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, where ${Z}^{\ifmmode\pm\else\textpm\fi{}}(4430)$ is used to denote the observed structure. The statistical significance of the observed peak is $6.5\ensuremath{\sigma}$. These results are obtained from a $605\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample that contains $657\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected near the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric energy ${e}^{+}{e}^{\ensuremath{-}}$ collider.

We study B→K(*)ℓ+ℓ− decays (ℓ=e, μ) based on a data sample of 657×106 BB¯ pairs collected with the Belle detector at the KEKB e+e− collider. We report the differential branching fraction, isospin asymmetry, K* polarization, and the forward-backward asymmetry (AFB) as functions of q2=Mℓℓ2c2. The fitted AFB spectrum exceeds the standard model expectation by 2.7 standard deviations. The measured branching fractions are B(B→K*ℓ+ℓ−)=(10.7−1.0+1.1±0.9)×10−7 and B(B→Kℓ+ℓ−)=(4.8−0.4+0.5±0.3)×10−7, where the first errors are statistical and the second are systematic, with the muon to electron ratios RK*=0.83±0.17±0.08 and RK=1.03±0.19±0.06.Received 5 April 2009DOI:https://doi.org/10.1103/PhysRevLett.103.171801©2009 American Physical Society

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.

Development of selective and sensitive methods for the detection of 2, 6-dipicolinic acid (DPA), a biomarker produced by bacterial spores, is of great significance for maintaining public health and food safety. Herein, a ratiometric fluorescence strategy using graphene carbon nitride (g-C3N4) coupled with Eu3+ is designed for the assay of DPA. As the concentration of DPA increases, the emission intensity of g-C3N4 kept constant which acted as a stable internal reference, while the fluorescence of Eu3+ was enhanced obviously due to the antenna effect. The linear calibration ranged from 0.1 to 15 μM with a detection limit of 13 nM was obtained. More Importantly, a paper-based sensor with a smartphone was successfully combined to perform colorimetric and visual detection of DPA in situ. This method has good performance for the detection of DPA, which is expected to broaden the application prospects of preliminary biomarker monitoring.

We report the observation of prompt J/psi via double cc; production from the e+e- continuum. In this process one cc; pair fragments into a J/psi meson while the remaining pair either produces a charmonium state or fragments into open charm. Both cases have been experimentally observed. We find cross sections of sigma[e+e- -->J/psieta(c)(gamma)]xB(eta(c)-->>or=4 charged)=(0.033(+0.007)(-0.006)+/-0.009) pb and sigma(e+e- -->J/psiD(*+)X)=(0.53(+0.19)(-0.15)+/-0.14) pb and infer sigma(e+e- -->J/psicc;)/sigma(e+e- -->J/psiX)=0.59(+0.15)(-0.13)+/-0.12. These results are obtained from a 46.2 fb(-1) data sample collected near the Upsilon(4S) resonance, with the Belle detector at the KEKB collider.

We have measured the branching fraction of the inclusive radiative B meson decay B --> X(s) gamma to be Br(B->X(s)gamma)=(3.36 +/- 0.53(stat) +/- 0.42(sys) +0.50-0.54(th)) x 10^{-4}. The result is based on a sample of 6.07 x 10^6 BBbar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.

We report the results of a study of charged B decays to the D+- pi-+ pi-+ and D*+- pi-+ pi-+ final states using complete D(*) reconstruction. The contributions of two-body B => D** pi decays with narrow (j=3/2) and broad (j=1/2) D** states have been determined and the masses and widths of four D** states have been measured. This is the first observation of the broad D*0_0 and D'0_1 mesons. The analysis is based on a data sample of 65 million B barB pairs collected in the Belle experiment.

We report the first observation of a charmoniumlike state recoiling from the J/psi in the inclusive process e+e- -->J/psi+anything at a mass of (3.943+/-0.006+/-0.006) GeV/c{2}. We also observe the decay of this state into D*D[over ] and determine its intrinsic width to be less than 52 MeV/c{2} at the 90% C.L. These results are obtained from a 357 fb{-1} data sample collected with the Belle detector near the Upsilon(4S) resonance, at the KEKB asymmetric-energy e+e- collider.

We report a fully inclusive measurement of the flavor changing neutral current decay b --> sgamma in the energy range 1.8 GeV < or = E*gamma < or = 2.8 GeV, covering 95% of the total spectrum. Using 140 fb(-1), we obtain B(b --> sgamma) = (3.55+/-0.32(+0.30+0.11)(-0.31-0.07)) x 10(-4), where the errors are statistical, systematic, and from theory corrections. We also measure the first and second moments of the photon energy spectrum above 1.8 GeV and obtain (Egamma) = 2.292+/-0.026+/-0.034 GeV and (E2gamma) - (Egamma)2 = 0.0305+/-0.0074+/-0.0063 GeV2, where the errors are statistical and systematic.

We observe evidence for D0−¯¯¯D0 mixing by measuring the difference in the apparent lifetime when a D0 meson decays to the CP eigenstates K+K− and π+π− and when it decays to the final state K−π+. We find the relative difference of the lifetimes yCP to be [1.31±0.32(stat)±0.25(syst)]%, 3.2 standard deviations from zero. We also search for a CP asymmetry between D0 and ¯¯¯D0 decays; no evidence for CP violation is found. These results are based on 540 fb−1 of data recorded by the Belle detector at the KEKB e+e− collider.Received 31 March 2007DOI:https://doi.org/10.1103/PhysRevLett.98.211803©2007 American Physical Society

We present an improved measurement of the standard model CP violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ (also known as $\mathrm{sin}2\ensuremath{\beta})$ based on a sample of $85\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral B meson is reconstructed in a $J/\ensuremath{\psi}{K}_{S}^{0},$ $\ensuremath{\psi}{(2S)K}_{S}^{0},$ ${\ensuremath{\chi}}_{c1}{K}_{S}^{0},$ ${\ensuremath{\eta}}_{c}{K}_{S}^{0},$ $J/\ensuremath{\psi}{K}^{*0},$ or $J/\ensuremath{\psi}{K}_{L}^{0}$ CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time interval between the two B meson decay points, we obtain $\mathrm{sin}2{\ensuremath{\varphi}}_{1}=0.719\ifmmode\pm\else\textpm\fi{}0.074(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.035(\mathrm{syst}).$

We report the first observation of a near-threshold enhancement in the D(0)D[over](0)pi(0) system from B-->D(0)D[over](0)pi(0)Kappa decays using a 414 fb(-1) data sample collected at the Upsilon(4S) resonance. The enhancement peaks at a mass M=3875.2+/-0.7(+0.3)/(-1.6) +/-0.8 MeV/c2 and the branching fraction for events in the peak is B(B-->D(0)D[over](0)pi(0)Kappa)=(1.22+/-0.31(+0.23)/(-0.30))x10(-4). The data were collected with the Belle detector at the KEKB energy-asymmetric e+ e- collider.

We report a high-statistics measurement of the branching fraction for τ -→ π -π 0 ν τ and the invariant mass spectrum of the produced π -π 0 system using 72.2 fb -1 of data recorded with the Belle detector at the KEKB asymmetric-energy e + e -collider.The branching fraction obtained is (25.24 ± 0.01 ± 0.39)%, where the first error is statistical and the second is systematic.The unfolded π -π 0 mass spectrum is used to determine resonance parameters for the ρ(770), ρ ′ (1450), and ρ ′′ (1700) mesons.We also use this spectrum to estimate the hadronic (2π) contribution to the anomalous magnetic moment of the muon (a ππ µ ).Our result for a ππ µ integrated over the mass range √ s = 2m π -1.8 GeV/c 2 is a ππ µ = (523.5 ± 1.5 (exp) ± 2.6 (Br) ± 2.5 (isospin)) × 10 -10 , where the first error is due to the experimental uncertainties, the second is due to the uncertainties in the branching fractions and the third is due to the uncertainties in the isospin-violating corrections.

We report the first observation of e;{+}e;{-}-->Upsilon(1S)pi;{+}pi;{-}, Upsilon(2S)pi;{+}pi;{-}, and first evidence for e;{+}e;{-}-->Upsilon(3S)pi;{+}pi;{-}, Upsilon(1S)K+K-, near the peak of the Upsilon(5S) resonance at sqrt[s] approximately 10.87 GeV. The results are based on a data sample of 21.7 fb;{-1} collected with the Belle detector at the KEKB e;{+}e;{-} collider. Attributing the signals to the Upsilon(5S) resonance, the partial widths Gamma(Upsilon(5S)-->Upsilon(1S)pi;{+}pi;{-})=0.59+/-0.04(stat)+/-0.09(syst) MeV and Gamma(Upsilon(5S)-->Upsilon(2S)pi;{+}pi;{-})=0.85+/-0.07(stat)+/-0.16(syst) MeV are obtained from the observed cross sections. These values exceed by more than 2 orders of magnitude the previously measured partial widths for dipion transitions between lower Upsilon resonances.

The old silicon vertex detector (SVD1) of the Belle detector, operating at the high-luminosity asymmetric energy e+e− collider KEKB, was replaced by an upgraded version (SVD2) in 2003. The new detector has modified geometry and redesigned readout electronics, providing a larger polar angle acceptance, better vertex resolution, improved radiation hardness and reduced dead time. The operation of the detector started successfully in October 2003. The basic concepts of the SVD2 design as well as its performance after 10 months of data taking are described in this paper.

The Collins effect connects transverse quark spin with a measurable azimuthal asymmetry in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods we measure statistically significant azimuthal asymmetries for charged pion pairs in e+e− annihilation at center-of-mass energies of 10.52 GeV and 10.58 GeV, which can be attributed to the fragmentation of primordial quarks with transverse spin components. The measurement was performed using a data set of 547 fb−1 collected by the Belle detector at KEKB improving the statistics of the previously published results by nearly a factor of 20.17 MoreReceived 19 May 2008DOI:https://doi.org/10.1103/PhysRevD.78.032011©2008 American Physical Society

We report on a search for the lepton flavor violating τ−→μ−γ and τ−→e−γ decays based on 535 fb−1 of data accumulated at the Belle experiment. No signal is found and we set 90% confidence level upper limits on the branching ratios B(τ−→μ−γ)<4.5×10−8 and B(τ−→e−γ)<1.2×10−7.

We report a study of the processes e+e−→J/ψD(*)¯¯¯D(*). In J/ψD∗¯¯¯D∗ we observe a significant enhancement in the D∗¯¯¯D∗ invariant mass spectrum, which we interpret as a new charmoniumlike state and denote X(4160). The X(4160) parameters are M=(4156+25−20±15) MeV/c2 and Γ=(139+111−61±21) MeV. We also report a new measurement of the X(3940) mass and width: M=(3942+7−6±6) MeV/c2 and Γ=(37+26−15±8) MeV. The analysis is based on a 693 fb−1 data sample recorded near the Υ(4S) resonance by the Belle detector at the KEKB asymmetric-energy collider.Received 5 October 2007DOI:https://doi.org/10.1103/PhysRevLett.100.202001©2008 American Physical Society

We present measurements of B+→¯¯¯D*0τ+ντ and B+→¯¯¯D0τ+ντ decays in a data sample of 657×106 B¯¯¯B pairs collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. We find 446+58−56 B+→¯¯¯D*0τ+ντ events with a significance of 8.1 standard deviations, and 146+42−41 B+→¯¯¯D0τ+ντ events with a significance of 3.5 standard deviations. The latter signal provides the first evidence for this decay mode. The measured branching fractions are B(B+→¯¯¯D*0τ+ντ)=(2.12+0.28−0.27(stat)±0.29(syst))% and B(B+→¯¯¯D0τ+ντ)=(0.77±0.22(stat)±0.12(syst))%.Received 13 May 2010DOI:https://doi.org/10.1103/PhysRevD.82.072005© 2010 The American Physical Society

We present a measurement of the charmless semileptonic decay $B^0\to\pi^-\ell^+\nu$ using a data sample containing 657$\times 10^6$ $B\bar{B}$ events collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider operating near the $\Upsilon(4S)$ resonance. We determine the total branching fraction of the decay, $\mathcal{B}(B^0\to\pi^-\ell^+\nu)=(1.49\pm 0.04{(\mathrm{stat})}\pm 0.07{(\mathrm{syst})})\times 10^{-4}$. We also report a new precise measurement of the differential decay rate, and extract the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$ using model-independent and -dependent approaches. From a simultaneous fit to the measured differential decay rate and lattice QCD results, we obtain $|V_{ub}|=(3.43\pm 0.33)\times 10^{-3}$, where the error includes both statistical and systematic uncertainties.

We report the observation of a narrow peak in the K(S)K-pi(+) invariant mass distribution in a sample of exclusive B-->KK(S)K-pi(+) decays collected with the Belle detector at the KEKB asymmetric e(+)e(-) collider. The measured mass of the peak is M=3654+/-6(stat)+/-8(syst) MeV/c(2), and we place a 90% confidence level upper limit on the width of Gamma<55 MeV/c(2). The properties agree with heavy-quark potential model expectations for the eta(c)(2S) meson, the n=2 singlet S charmonium state.

We report results on the Dalitz analysis of three-body charmless B + → K + π + π -and B + → K + K + K -decays based on a 140 fb -1 data sample collected with the Belle detector.Measurements of branching fractions for quasi-two-body decays to scalar-pseudoscalar states: B + → f 0 (980)K + , B + → K * 0 (1430) 0 π + , and to vector-pseudoscalar states:Upper limits on decays to some pseudoscalar-tensor final states are reported.We also report the measurement of the B + → χ c0 K + branching fraction in two χ c0 decays channels: χ c0 → π + π -and χ c0 → K + K -.

We have searched for a CP violation signature arising from an electric dipole moment (dτ) of the τ lepton in the e+e−→τ+τ− reaction. Using an optimal observable method and 29.5 fb−1 of data collected with the Belle detector at the KEKB collider at s=10.58 GeV, we find Re(dτ)=(1.15±1.70)×10−17 ecm and Im(dτ)=(−0.83±0.86)×10−17 ecm and set the 95% confidence level limits −2.2×10−17<Re(dτ)<4.5×10−17 ecm and −2.5×10−17<Im(dτ)<0.8×10−17 ecm.

We present an improved measurement of the branching fraction for the electroweak penguin process B-&gt;Xsll, where l is an electron or a muon and Xs is a hadronic system containing an s-quark. The measurement is based on a sample of 152*10^6 Upsilon(4S) -&gt; BB events collected with the Belle detector at the KEKB energy asymmetric e+e- collider. The Xs hadronic system is reconstructed from one K^{+-} or K^{0}_{S} and up to four pions, where at most one pion can be neutral. Averaging over both lepton flavors, the inclusive branching fraction is measured to be Br(B-&gt;Xsll)=(4.11+-0.83(stat)+0.85-0.81(syst))*10^{-6} for M_ll &gt; 0.2GeV/c2.

We report evidence for the decay ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$. The analysis is based on a data sample of ${\mathrm{152}\mathrm{\ifmmode\times\else\texttimes\fi{}}\mathrm{10}}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB ${e}^{+}{e}^{\ensuremath{-}}$ storage ring. We detect a signal for ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ with a significance of 3.4 standard deviations, and measure the branching fraction to be $\mathrm{[}\mathrm{1.7}\ifmmode\pm\else\textpm\fi{}\mathrm{0.6}\mathrm{(}\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{)}\ifmmode\pm\else\textpm\fi{}\mathrm{0.2}\mathrm{(}\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{)}\mathrm{]}\ifmmode\times\else\texttimes\fi{}{\mathrm{10}}^{\ensuremath{-}\mathrm{6}}$.

We present a new analysis of double charmonium production in e + e -annihilation.The observation of the processes e + e -→ J/ψ ηc, J/ψ χc0, and J/ψ ηc(2S) is confirmed using a dataset more than three times larger than that of Belle's previous report, and no evidence for the process e + e -→ J/ψ J/ψ is found.We perform an angular analysis for J/ψ ηc production and set an upper limit on the production of J/ψ J/ψ.Processes of the type e + e -→ ψ(2S)(cc)res have been observed for the first time; their rates are found to be comparable to those of e + e -→ J/ψ(cc)res processes.

We report measurements of the properties of the D(+)(sJ)(2317) and D(+)(sJ)(2457) resonances produced in continuum e(+)e(-) annihilation near sqrt[s]=10.6 GeV. The analysis is based on an 86.9 fb(-1) data sample collected with the Belle detector at KEKB. We determine the masses to be M(D(+)(sJ)(2317))=2317.2+/-0.5(stat)+/-0.9(syst) MeV/c(2) and M(D(+)(sJ)(2457))=2456.5+/-1.3(stat)+/-1.3(syst) MeV/c(2). We observe the radiative decay mode D(+)(sJ)(2457)-->D(+)(s)gamma and the dipion decay mode D(+)(sJ)(2457)-->D(+)(s)pi(+)pi(-) and determine their branching fractions. No corresponding decays are observed for the D(sJ)(2317) state. These results are consistent with the spin-parity assignments of 0(+) for the D(sJ)(2317) and 1(+) for the D(sJ)(2457).

We report evidence for direct CP violation in the decay B0-->K+pi(-) with 253 fb(-1) of data collected with the Belle detector at the KEKB e(+)e(-) collider. Using 275x10(6) BB pairs we observe a B-->K+/-pi(-/+) signal with 2140+/-53 events. The measured CP violating asymmetry is A(CP)(K+pi(-))=-0.101+/-0.025(stat)+/-0.005(syst), corresponding to a significance of 3.9sigma including systematics. We also search for CP violation in the decays B+-->K+pi(0) and B+-->pi(+)pi(0). The measured CP violating asymmetries are A(CP)(K+pi(0))=0.04+/-0.05(stat)+/-0.02(syst) and A(CP)(pi(+)pi(0))=-0.02+/-0.10(stat)+/-0.01(syst), corresponding to the intervals -0.05<A(CP)(K+pi(0))<0.13 and -0.18<A(CP)(pi(+)pi(0))<0.14 at 90% confidence level.

We present a study of the decay τ−→KSπ−ντ using a 351 fb−1 data sample collected with the Belle detector. The analysis is based on 53,110 lepton-tagged signal events. The measured branching fraction B(τ−→KSπ−ντ)=(0.404±0.002(stat.)±0.013(syst.))% is consistent with the world average value and has better accuracy. An analysis of the KSπ− invariant mass spectrum reveals contributions from the K∗(892)− as well as other states. For the first time the K∗(892)− mass and width have been measured in τ decay: M(K∗(892)−)=(895.47±0.20(stat.)±0.44(syst.)±0.59(mod.))MeV/c2, Γ(K∗(892)−)=(46.2±0.6(stat.)±1.0(syst.)±0.7(mod.))MeV. The K∗(892)− mass is significantly different from the current world average value.

We present the first measurement of decay amplitudes in B→φK* and measurements of branching fractions in B→φK(*) decays based on 78.1 fb−1 of data recorded at the Υ(4S) resonance with the Belle detector at the KEKB e+e− storage ring. The decay amplitudes for the different φK*0 helicity states are measured from the angular distributions of final state particles in the transversity basis. The longitudinal and transverse complex amplitudes are |A0|2=0.43±0.09±0.04, |A⊥|2=0.41±0.10±0.04, arg(A∥)=−2.57±0.39±0.09, and arg(A⊥)=0.48±0.32±0.06. The direct CP-violating asymmetries are found to be consistent with zero.Received 8 July 2003DOI:https://doi.org/10.1103/PhysRevLett.91.201801©2003 American Physical Society

We present improved measurements of CP-violation parameters in B0→ϕK0, η′K0, K0SK0SK0S decays based on a sample of 535×106 B¯¯¯B pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e− collider. We obtain sin2ϕeff1=+0.64±0.10(stat)±0.04(syst) for B0→η′K0, +0.50±0.21(stat)±0.06(syst) for B0→ϕK0, and +0.30±0.32(stat)±0.08(syst) for B0→K0SK0SK0S decays. We have observed CP violation in the B0→η′K0 decay with a significance of 5.6 standard deviations. We also perform an improved measurement of CP asymmetries in B0→J/ψK0 decays and obtain sin2ϕ1=+0.642±0.031(stat)±0.017(syst).Received 2 October 2006DOI:https://doi.org/10.1103/PhysRevLett.98.031802©2007 American Physical Society

We report a measurement of ${D}^{0}\ensuremath{-}{\overline{D}}^{0}$ mixing parameters in ${D}^{0}\ensuremath{\rightarrow}{K}_{S}^{0}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays using a time-dependent Dalitz-plot analysis. We first assume $CP$ conservation and subsequently allow for $CP$ violation. The results are based on $540\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data accumulated with the Belle detector at the KEKB ${e}^{+}{e}^{\ensuremath{-}}$ collider. Assuming negligible $CP$ violation, we measure the mixing parameters $x=(0.80\ifmmode\pm\else\textpm\fi{}{0.29}_{\ensuremath{-}0.07\ensuremath{-}0.14}^{+0.09+0.10})%$ and $y=(0.33\ifmmode\pm\else\textpm\fi{}{0.24}_{\ensuremath{-}0.12\ensuremath{-}0.08}^{+0.08+0.06})%$, where the errors are statistical, experimental systematic, and systematic due to the Dalitz decay model, respectively. Allowing for $CP$ violation, we obtain the $CP$-violating parameters $|q/p|={0.86}_{\ensuremath{-}0.29\ensuremath{-}0.03}^{+0.30+0.06}\ifmmode\pm\else\textpm\fi{}0.08$ and $\mathrm{arg}(q/p)=(\ensuremath{-}{14}_{\ensuremath{-}18\ensuremath{-}3\ensuremath{-}4}^{+16+5+2})\ifmmode^\circ\else\textdegree\fi{}$.

We report a measurement of the exclusive e+e−→D(*)±D*∓ cross section as a function of center-of-mass energy near the D(*)±D*∓ threshold with initial-state radiation. A partial reconstruction technique is used to increase the efficiency and to suppress background. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 547.8 fb−1.Received 12 January 2007DOI:https://doi.org/10.1103/PhysRevLett.98.092001©2007 American Physical Society

We present a study of B → X(3872)K with X(3872) decaying to D * 0 D0 using a sample of 657 million B B pairs recorded at the Υ(4S) resonance with the Belle detector at the KEKB asymmetricenergy e + e -collider.Both D * 0 → D 0 γ and D * 0 → D 0 π 0 decay modes are used.We find a peak of 50.1 +14.8 -11.1 events with a mass of (3872.9+0.6 +0.4 -0.4 -0.5 ) MeV/c 2 , a width of (3.9 +2.8 +0.2 -1.4 -1.1 ) MeV/c 2 and a product branching fraction B(B → X(3872)K)×B(X(3872) → D * 0 D0 ) = (0.80±0.20±0.10)×10 - , where the first errors are statistical and the second ones are systematic.The significance of the signal is 6.4σ.The difference between the fitted mass and the D * 0 D0 threshold is calculated to be (1.1 +0.6 +0.1 -0.4 -0.3 ) MeV/c 2 .We also obtain an upper limit on the product of branching fractions B(B → Y (3940)K) × B(Y (3940) → D * 0 D0 ) of 0.67 × 10 -4 at 90% CL.

Using 605 fb(-1) of data collected at the Upsilon(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B-->X(s)gamma. For the lower photon energy thresholds of 1.7, 1.8, 1.9, and 2.0 GeV, as defined in the rest frame of the B meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7 GeV threshold we obtain the partial branching fraction BF(B-->X(s)}gamma)=(3.45+/-0.15+/-0.40)x10(-4), where the errors are statistical and systematic.

In geotechnical engineering construction, the surrounding rock is often disturbed by dynamic loads such as blasting and earthquakes, resulting in varying degrees of disturbance damage. To study the fracture fractal characteristics and energy dissipation law of different dynamic disturbance-damaged rock masses were subjected to the same failure impact. A series of laboratory tests were carried out by means of a split Hopkinson pressure bar system. Firstly, the disturbance impact test was carried out and the test variables were impact velocity (including high-velocity impact in the velocity range of 1.65 m/s and low-velocity impact in the velocity range of 1.27 m/s) and cycle impact times. Based on the disturbance impact test, the failure impact test with the same velocity (with an average velocity of 3.2 m/s) was carried out to study the relationship between the fractal characteristics of fragmentation and energy dissipation. The results show that the macro damage (crack propagation, edge fracture, and surface particle detachment) increases with the increase of disturbance times. At the same time, after the impact of low-velocity disturbance, the fragments of disturbed specimens have larger fractal dimensions than those of undisturbed and high-velocity disturbed specimens. This indicates that low-velocity impact may produce internal damage that cannot be easily observed directly. The energy dissipation law shows that the high-velocity disturbance impact specimens have higher reflection energy and transmission energy than the low-velocity impact specimens. The regulation and rates of dissipated energy and energy dissipation density are, on the contrary, indicating that the energy utilization rate of the specimen is higher under the impact of low-velocity disturbance. Under the dynamic stress disturbance, the final fracture fractal dimension of the specimen is negatively correlated with the reflected energy during the disturbance impact and positively correlated with the dissipation energy and dissipation energy density. Finally, the meso failure mechanism of weakly cemented red sandstone, subject to disturbance, was analysed based on SEM photos of debris.

Magnetic CoFe [email protected] graphitized carbon nano-catalyst ([email protected]) was synthesized by hydrothermal method and chemical deposition method, which could couple with peroxymonosulfate (PMS) to degrade herbicide bensulfuron-methyl (BSM). CoFe alloy nanoparticles were encapsulated in N-doped graphitized carbon yarn-like material, providing strong stability and high corrosion resistance properties of them. Furthermore, CoFe alloy can make great improvement of degradation performance via tuning metal site's intrinsic performance of the Fermi energy level density of states. [email protected] (k = 0.4 min−1) displayed better catalytic performance than CoFe2O4 (k = 0.14 min−1) because of the intrinsic strengths of each component, synergy between cobalt and iron, doping of nitrogen atoms and graphitized carbon and unique electronic properties. 10 mg·L−1 bensulfuron-methyl was degraded completely by the combination of [email protected] and PMS within 10 min at pH 7. Magnetic [email protected] could be separated from solution by an external magnet, thus making convenience to collect catalyst and avoiding second pollution. After 15 recycling use of [email protected], the BSM degradation efficiency could still be maintained at 95%. [email protected]/PMS system exhibited stable degradation ability over a wide pH range (3–8) and displayed strong tolerance to real water samples. The main active species, possible BSM degradation pathways and potential reaction mechanism of [email protected]/PMS were systematically explored. Thus, our finding can provide an environmental friendly, efficient and easy recycle catalyst to degrade refractory organic matters by PMS activation.

Yade is an extensible open-source framework for discrete numerical models, focused on the Discrete Element Method. The computation parts are written in c++ using a flexible object model and allowing independent implementation of new algorithms and interfaces. Python is used for rapid and concise scene construction, simulation control, postprocessing and debugging. Yade is located at yade-dem.org, which contains this documentation. Development is kindly hosted on launchpad and GitLab ; they are used for source code, bug tracking and source downloads and more. Building, regression tests and packages distribution are hosted on servers of the Grenoble Geomechanics group at Laboratoire 3SR, UMS Gricad and Gda\'nsk University of Technology. Yade supports high precision calculations and Python 3. The development branch is on GitLab.

We present a measurement of the standard model CP violation parameter sin2 phi(1) (also known as sin2beta) based on a 10.5 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. One neutral B meson is reconstructed in the J/psiK(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psiK(L), or J/psipi(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin2 phi(1) = 0.58(+0.32)(-0.34)(stat)+0.09-0.10(syst).

We present measurements of decay amplitudes and triple-product correlations in B→ϕK∗ decays based on 253 fb−1 of data recorded at the Υ(4S) resonance with the Belle detector at the KEKB e+e− storage ring. The decay amplitudes for the three different helicity states are determined from the angular distributions of final-state particles. The longitudinal polarization amplitudes are found to be 0.45±0.05±0.02 for B0→ϕK*0 and 0.52±0.08±0.03 for B+→ϕK*+ decays. CP- and T-odd CP-violating triple-product asymmetries are measured to be consistent with zero.Received 6 March 2005DOI:https://doi.org/10.1103/PhysRevLett.94.221804©2005 American Physical Society

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.

The B meson decay modes B --> D p pbar and B --> D* p pbar have been studied using 29.4 fb^{-1} of data collected with the Belle detector at KEKB. The B0bar --> D0 p pbar and B0bar --> D*0 p pbar decays have been observed for the first time with branching fractions Br(B0bar --> D0 p pbar) =(1.18\pm 0.15\pm 0.16) 10^{-4} and Br(B0bar --> D*0 p pbar) =(1.20^{+0.33}_{-0.29}\pm 0.21) 10^{-4}. No signal has been found for the B+ --> D+ p pbar and B+ --> D*+ p pbar decay modes, and the corresponding upper limits at 90% C.L. are presented.

We report the first observation of the charmless vector-vector decay process B∓→ρ∓ρ0. The measurement uses a 78 fb−1 data sample collected with the Belle detector at the KEKB asymmetric e+e− collider operating at the Υ(4S) resonance. We obtain a branching fraction of B(B∓→ρ∓ρ0)=[31.7±7.1(stat)−6.7+3.8(syst)]×10−6. An analysis of the ρ helicity-angle distributions gives a longitudinal polarization fraction of ΓL/Γ=0.95±0.11(stat)±0.02(syst). We also measure the direct-CP-violating asymmetry ACP(B∓→ρ∓ρ0)=0.00±0.22(stat)±0.03(syst).Received 3 June 2003DOI:https://doi.org/10.1103/PhysRevLett.91.221801©2003 American Physical Society

We report measurements of the radiative decay B → K * γ.The analysis is based on a data sample containing 85.0 × 10 6 B meson pairs collected by the Belle detector at the KEKB storage ring.We measure branching fractions of B(B 0 → K * 0 γ) = (4.01 ± 0.21 ± 0.17) × 10 -5 and B(B + → K * + γ) = (4.25 ± 0.31 ± 0.24) × 10 -5 , where the first and second errors are statistical and systematic, respectively.The isospin asymmetry between B 0 and B + decay widths is measured to be ∆0+ = +0.012± 0.044 ± 0.026.We search for a partial rate asymmetry between CP conjugate modes, and find ACP (B → K * γ) = -0.015± 0.044 ± 0.012.

We have performed a search for the lepton-flavor-violating decay tau -> mu gamma using a data sample of 86.3fb^{-1} accumulated by the Belle detector at KEK. No evidence for a signal is seen, and we set an upper limit for the branching fraction of B(tau -> mu gamma) < 3.1 x 10^{-7} at the 90% confidence level.

We present an improved measurement of CP-violation parameters in B0-->phiK(0)(S), K(+)K(-)K(0)(S), and eta(')K(0)(S) decays based on a 140 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the three modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. We find that the observed CP asymmetry in the B-->phiK(0)(S) decay differs from the standard model (SM) expectation by 3.5 standard deviations, while the other cases are consistent with the SM.

We present a precise measurement of the standard model $CP$-violation parameter $\mathrm{sin}2{\ensuremath{\phi}}_{1}$, the direct $CP$ violation parameter $|\ensuremath{\lambda}|$, the lifetimes of charged and neutral $B$ mesons and their ratio, and the ${B}^{0}$-${\overline{B}}^{0}$ mixing parameter $\ensuremath{\Delta}{m}_{d}$ based on a sample of $152\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One of two $B$ mesons is fully reconstructed in a $CP$-eigenstate or a flavor-eigenstate decay channel. The flavor of the accompanying $B$ meson is identified from its decay products. From the distributions of the time interval between the two $B$ meson decay points, we obtain $\mathrm{sin}2{\ensuremath{\phi}}_{1}=0.728\ifmmode\pm\else\textpm\fi{}0.056(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.023(\mathrm{syst})$, $|\ensuremath{\lambda}|=1.007\ifmmode\pm\else\textpm\fi{}0.041(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.033(\mathrm{syst})$, ${\ensuremath{\tau}}_{{B}^{0}}=[1.534\ifmmode\pm\else\textpm\fi{}0.008(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.010(\mathrm{syst})]\text{ }\text{ }\mathrm{ps}$, ${\ensuremath{\tau}}_{{B}^{+}}=[1.635\ifmmode\pm\else\textpm\fi{}0.011(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.011(\mathrm{syst})]\text{ }\text{ }\mathrm{ps}$, ${\ensuremath{\tau}}_{{B}^{+}}/{\ensuremath{\tau}}_{{B}^{0}}=1.066\ifmmode\pm\else\textpm\fi{}0.008(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.008(\mathrm{syst})$ and $\ensuremath{\Delta}{m}_{d}=[0.511\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.006{(\mathrm{syst})]\text{ }\text{ }\mathrm{ps}}^{\ensuremath{-}1}$. The results for $\mathrm{sin}2{\ensuremath{\phi}}_{1}$ and $|\ensuremath{\lambda}|$ are consistent with the standard model expectations. The significance of the observed deviation from unity in the lifetime ratio exceeds 5 standard deviations.

We report the first measurement of the forward-backward asymmetry and the ratios of Wilson coefficients A 9 /A 7 and A 10 /A 7 in B → K * ℓ + ℓ -, where ℓ represents an electron or a muon.We observe a large integrated forward-backward asymmetry with a significance of 3.4σ.The results are obtained from a data sample containing 386 ×10 6 B B pairs that were collected on the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e -collider.

We measure the CP-violating asymmetries in decays to the D0 -> K+K- and D0 -> pi+pi- CP eigenstates using 540 fb^{-1} of data collected with the Belle detector at or near the Upsilon(4S) resonance. Cabibbo-favored D0 -> K-pi+ decays are used to correct for systematic detector effects. The results, A_{CP}^{KK} = (-0.43 +- 0.30 +- 0.11)% and A_{CP}^{pipi} = (+0.43 +- 0.52 +- 0.12)%, are consistent with no CP violation.

We measure the production cross sections for e+e- -> Upsilon(1S)pi+pi-, Upsilon(2S)pi+pi-, and Upsilon(3S)pi+pi- as a function of sqrt{s} between 10.83 GeV and 11.02 GeV. The data consists of 8.1 fb^-1 collected with the Belle detector at the KEKB e+e- collider. We observe enhanced production in all three final states that does not agree well with the conventional Upsilon(10860) lineshape. A fit using a Breit-Wigner resonance shape yields a peak mass of [10888.4 +2.7/-2.6 (stat) +- 1.2 (syst)] MeV/c^2 and a width of [30.7 +8.3/-7.0 (stat) +- 3.1 (syst)] MeV/c^2.

We present a measurement of the decay B−→τ−ν¯τ using a data sample containing 657×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. A sample of B+B− pairs are tagged by reconstructing one B+ meson decaying semileptonically. We detect the B−→τ−ν¯τ candidate in the recoil. We obtain a signal with a significance of 3.6 standard deviations including systematic uncertainties, and measure the branching fraction to be B(B−→τ−ν¯τ)=[1.54−0.37+0.38(stat)−0.31+0.29(syst)]×10−4. This result confirms the evidence for B−→τ−ν¯τ obtained in a previous Belle measurement that used a hadronic B tagging method.Received 21 June 2010DOI:https://doi.org/10.1103/PhysRevD.82.071101© 2010 The American Physical Society

This article describes a determination of the Cabibbo-Kobayashi-Maskawa matrix element $|{V}_{cb}|$ from the decay ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ using $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of Belle data collected near the $\ensuremath{\Upsilon}(4S)$ resonance. We simultaneously measure the product of the form factor normalization $\mathcal{F}(1)$ and the matrix element $|{V}_{cb}|$ as well as the three parameters ${\ensuremath{\rho}}^{2}$, ${R}_{1}(1)$ and ${R}_{2}(1)$, which determine the form factors of this decay in the framework of the heavy quark effective theory. The results, based on about 120 000 reconstructed ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ decays, are ${\ensuremath{\rho}}^{2}=1.214\ifmmode\pm\else\textpm\fi{}0.034\ifmmode\pm\else\textpm\fi{}0.009$, ${R}_{1}(1)=1.401\ifmmode\pm\else\textpm\fi{}0.034\ifmmode\pm\else\textpm\fi{}0.018$, ${R}_{2}(1)=0.864\ifmmode\pm\else\textpm\fi{}0.024\ifmmode\pm\else\textpm\fi{}0.008$ and $\mathcal{F}(1)|{V}_{cb}|=(34.6\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. The branching fraction of ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ is measured at the same time; we obtain a value of $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\ell}}^{+}{\ensuremath{\nu}}_{\ensuremath{\ell}})=(4.58\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.26)%$. The errors correspond to the statistical and systematic uncertainties. These results give the most precise determination of the form factor parameters and $\mathcal{F}(1)|{V}_{cb}|$ to date. In addition, a direct, model-independent determination of the form factor shapes has been carried out.

We report measurements of the branching fractions and direct CP asymmetries (A_{CP}) for B->K pi, pi pi and KK decays (but not pi^0 pi^0) based on the final data sample of 772x10^6 B B-bar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+ e^- collider. We set a 90% confidence-level upper limit for K^+- K^-+ at 2.0x10^{-7}; all other decays are observed with branching fractions ranging from 10^{-6} to 10^{-5}. In the $B^0/B^0-bar -> K^+-\pi^-+ mode, we confirm Belle's previously reported large A_{CP} with a value of -0.069 +- 0.014 +- 0.007 and a significance of 4.4 sigma. For all other flavor-specific modes, we find A_{CP} values consistent with zero, including A_{CP}(K^+- \pi^0) = +0.043 +- 0.024 +- 0.007 with 1.8 sigma significance. The difference of CP asymmetry between B^+- -> K^+- pi^0 and B^0/B^0-bar -> K^+-\pi^-+ is found to be Delta A_{K pi} equiv A_{CP} (K^+ pi^0) - A_{CP}(K^+ pi^-) = +0.112 +- 0.027 +- 0.007 with 4.0 sigma significance. We also calculate the ratios of partial widths for the B-> K pi decays. Using our results, we test the validity of the sum rule A_{CP}(K^+ pi^-) + A_{CP}(K^0\pi^+) x Gamma(K^0\pi^+)/Gamma(K^+ pi^-)} - A_{CP}(K^+ pi^0)x 2Gamma(K^+ pi^0)/Gamma(K^+ pi^-) - A_{CP}(K^0 pi^0)x 2Gamma(K^0 pi^0)/Gamma(K^+ pi^-) = 0 and obtain a sum of -0.270 +- 0.132 +- 0.060 with 1.9 sigma significance.

In the original article, it was found in Monte Carlo simulations that the reconstructed A₀ results are roughly consistent with the generated asymmetries, while the A₁₂ results systematically underestimate the generated asymmetries. This underestimation can be attributed to the difference between the reconstructed thrust axis and the original quark-antiquark axis. The corresponding correction factors are 1.6 ± 0.04 for the A₁₂ results and 1.11 ± 0.05 for the A₀ results. Because of a flaw in the original analysis program, these correction factors were not applied to the AUC-type asymmetries in Table V as well as in some figures. In addition, a small mistake in the error propagation in the charm correction resulted in slightly underestimated statistical uncertainties. These omissions affect all but the charm asymmetry results. The correct central values are therefore given in Tables IV and V of this Erratum. The systematic uncertainties of the original publication remain unchanged.

Multilevel image segmentation is time-consuming and involves large computation. The firefly algorithm has been applied to enhancing the efficiency of multilevel image segmentation. However, in some cases, firefly algorithm is easily trapped into local optima. In this paper, an improved firefly algorithm (IFA) is proposed to search multilevel thresholds. In IFA, in order to help fireflies escape from local optima and accelerate the convergence, two strategies (i.e., diversity enhancing strategy with Cauchy mutation and neighborhood strategy) are proposed and adaptively chosen according to different stagnation stations. The proposed IFA is compared with three benchmark optimal algorithms, that is, Darwinian particle swarm optimization, hybrid differential evolution optimization, and firefly algorithm. The experimental results show that the proposed method can efficiently segment multilevel images and obtain better performance than the other three methods.

In this study, the microstructure and mechanical properties of cobalt-based superalloys by internal nitridation at 1100 °C, 1150 °C, and 1200 °C were characterised in detail by transmission electron microscope (TEM), electron probe microanalysis (EPMA), electron backscatter diffraction (EBSD) and microhardness testing. The results show that with an increase in the internal nitridation temperature, the nitridation layer thickness of cobalt-based superalloys gradually increases to 898 μm. Internal nitridation at 1200 °C for 10 h exhibits the densest nitrides and the thickest layer. The precipitates were then dispersed in the matrix. The precipitates are mainly cubic, spherical, and cruciform (Ti, Nb)(C, N). Small amounts of blocky AlN and Cr2N were observed in the outer nitridation layer. Internal nitridation significantly improves the mechanical properties of cobalt-based superalloys by precipitation and solution strengthening. The yield strength increased by 105 % at room temperature (RT). Compared with the yield strength of 100 MPa for the as-received alloy at 800 °C, the internal nitridation alloy could still maintain good mechanical properties: a yield strength 300 MPa and an elongation 32%. In addition, because of the low diffusion activation energy of nitrogen in cobalt-based superalloys, internal nitridation is suitable for strengthening cobalt-based superalloys, expanding their application prospects in engineering structural materials.

We present a measurement of the unitarity triangle angle ${\ensuremath{\phi}}_{3}$ using a Dalitz plot analysis of the three-body decay of the neutral $D$ meson from the ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{(*)}{K}^{\ifmmode\pm\else\textpm\fi{}}$ process. The method employs the interference between ${D}^{0}$ and $\overline{{D}^{0}}$ to extract both the weak and strong phases. We apply this method to a $140\text{ }\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample collected by the Belle experiment. The analysis uses the modes ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}D{K}^{\ifmmode\pm\else\textpm\fi{}}$ and ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{*}{K}^{\ifmmode\pm\else\textpm\fi{}}$, ${D}^{*}\ensuremath{\rightarrow}D{\ensuremath{\pi}}^{0}$, where the neutral $D$ meson decays into ${K}_{S}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. We obtain 146 signal candidates for ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}D{K}^{\ifmmode\pm\else\textpm\fi{}}$ and 39 candidates for ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{*}{K}^{\ifmmode\pm\else\textpm\fi{}}$. From a combined maximum likelihood fit to the ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}D{K}^{\ifmmode\pm\else\textpm\fi{}}$ and ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{*}{K}^{\ifmmode\pm\else\textpm\fi{}}$ modes, we obtain ${\ensuremath{\phi}}_{3}=77\ifmmode^\circ\else\textdegree\fi{}\genfrac{}{}{0}{}{+17\ifmmode^\circ\else\textdegree\fi{}}{\ensuremath{-}19\ifmmode^\circ\else\textdegree\fi{}}(\mathrm{\text{stat}})\ifmmode\pm\else\textpm\fi{}13\ifmmode^\circ\else\textdegree\fi{}(\mathrm{\text{syst}})\ifmmode\pm\else\textpm\fi{}11\ifmmode^\circ\else\textdegree\fi{}(\mathrm{\text{model}})$. The corresponding 2 standard deviation interval is $26\ifmmode^\circ\else\textdegree\fi{}&lt;{\ensuremath{\phi}}_{3}&lt;126\ifmmode^\circ\else\textdegree\fi{}$.

We report the observation of the flavor-changing neutral current decay B-->K(*)l(+)l(-) and an im-proved measurement of the decay B-->Kl(+)l(-), where l represents an electron or a muon, with a data sample of 140 fb(-1) accumulated at the Upsilon(4S) resonance with the Belle detector at KEKB. The results for the branching fractions are B(B-->K(*)l(+)l(-))=(11.5(+2.6)(-2.4)+/-0.8+/-0.2)x10(-7) and B(B-->Kl(+)l(-))=(4.8(+1.0)(-0.9)+/-0.3+/-0.1)x10(-7), where the first error is statistical, the second is systematic and the third is from model dependence.

We report a search for the flavor-changing neutral current decay B-->K(*)l+l- using a 29.1 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring. We observe the decay process B-->Kl+l-(l = e, mu), for the first time, with a branching fraction of B(B-->Kl+l-) = (0.75(+0.25)(-0.21)+/-0.09)x10(-6).

We report measurements of the branching fractions for $B^0\to\pi^+\pi^-$, $K^+\pi^-$, $K^+K^-$ and $K^0\pi^0$, and $B^+\to\pi^+\pi^0$, $K^+\pi^0$, $K^0\pi^+$ and $K^+\bar{K}{}^0$. The results are based on 10.4 fb$^{-1}$ of data collected on the $\Upsilon$(4S) resonance at the KEKB $e^+e^-$ storage ring with the Belle detector, equipped with a high momentum particle identification system for clear separation of charged $\pi$ and $K$ mesons. We find ${\cal B}(B^0\to\pi^+\pi^-) =(0.56^{+0.23}_{-0.20}\pm 0.04)\times 10^{-5}$, ${\cal B}(B^0\to K^+\pi^-) =(1.93^{+0.34 +0.15}_{-0.32 -0.06})\times 10^{-5}$, ${\cal B}(B^+\to K^+\pi^0) =(1.63^{+0.35 +0.16}_{-0.33 -0.18})\times 10^{-5}$, ${\cal B}(B^+\to K^0\pi^+) =(1.37^{+0.57 +0.19}_{-0.48 -0.18})\times 10^{-5}$, and ${\cal B}(B^0\to K^0\pi^0) =(1.60^{+0.72 +0.25}_{-0.59 -0.27})\times 10^{-5}$, where the first and second errors are statistical and systematic. We also set upper limits of ${\cal B}(B^+\to\pi^+\pi^0)<1.34\times 10^{-5}$, ${\cal B}(B^0\to K^+K^-)<0.27\times 10^{-5}$, and ${\cal B}(B^+\to K^+\bar{K}{}^0)<0.50\times 10^{-5}$ at the 90% confidence level.

We report the first observation of a b -> u type charmless baryonic B decay, B+ -> p pbar pi+, as well as b -> s type B0 -> p pbar K0 and B+ -> p pbar K*+ decays. The analysis is based on a 78fb^{-1} data sample recorded on the Upsilon(4S) resonance with the Belle detector at KEKB. We find BF(B+ -> p pbar pi+) = (3.06^{+0.73}_{-0.62} \pm 0.37)*10^{-6}, BF(B0 -> p pbar K0) =(1.88^{+0.77}_{-0.60} \pm 0.23)*10^{-6}, and BF(B+ -> p pbar K*+) = (10.3^{+3.6 + 1.3}_{-2.8 -1.7})*10^{-6}. We also update BF(B+ -> p pbar K+) = (5.66^{+0.67}_{-0.57} \pm 0.62)* 10^{-6}, and present an upper limit on BF(B0 -> p pbar K*0) at the 90% confidence level. A common feature of the observed decay modes is threshold peaking in baryon pair invariant mass.

We report the results of a search for D0-D0 mixing in D0 --> K+ pi- decays based on 400 fb(-1) of data accumulated by the Belle detector at KEKB. Both assuming CP conservation and allowing for CP violation, we fit the decay-time distribution for the mixing parameters x and y, as well as for the parameter R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays. The 95% confidence level region in the (x'2,y') plane is obtained using a frequentist method. Assuming CP conservation, we find x'2 < 0.72 x 10(-3) and -9.9 x 10(-3) < y' < 6.8 x 10(-3) at the 95% confidence level; these are the most stringent constraints on the mixing parameters to date. The no-mixing point (0,0) has a confidence level of 3.9%. Assuming no mixing, we measure R(D) = (0.377 +/- 0.008 +/- 0.005)%.

We present a measurement of the unitarity triangle angle ${\ensuremath{\phi}}_{3}$ using a Dalitz plot analysis of the ${K}_{S}^{0}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay of the neutral $D$ meson from the ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{D}^{(*)}{K}^{(*)\ifmmode\pm\else\textpm\fi{}}$ process. The method exploits the interference between ${D}^{0}$ and ${\overline{D}}^{0}$ to extract the angle ${\ensuremath{\phi}}_{3}$, strong phase $\ensuremath{\delta}$ and the ratio $r$ of suppressed and allowed amplitudes. We apply this method to a $357\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected by the Belle experiment. The analysis uses three modes: ${B}^{+}\ensuremath{\rightarrow}D{K}^{+}$, ${B}^{+}\ensuremath{\rightarrow}{D}^{*}{K}^{+}$ with ${D}^{*}\ensuremath{\rightarrow}D{\ensuremath{\pi}}^{0}$, and ${B}^{+}\ensuremath{\rightarrow}D{K}^{*+}$ with ${K}^{*+}\ensuremath{\rightarrow}{K}_{S}^{0}{\ensuremath{\pi}}^{+}$, as well as the corresponding charge-conjugate modes. From a combined maximum likelihood fit to the three modes, we obtain ${\ensuremath{\phi}}_{3}=53\ifmmode^\circ\else\textdegree\fi{}\genfrac{}{}{0}{}{+15\ifmmode^\circ\else\textdegree\fi{}}{\ensuremath{-}18\ifmmode^\circ\else\textdegree\fi{}}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}3\ifmmode^\circ\else\textdegree\fi{}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}9\ifmmode^\circ\else\textdegree\fi{}(\mathrm{\text{model}})$. The corresponding 2 standard deviation interval is $8\ifmmode^\circ\else\textdegree\fi{}&lt;{\ensuremath{\phi}}_{3}&lt;111\ifmmode^\circ\else\textdegree\fi{}$.

We report the first observation of CP-violating asymmetries in B0 --> pi+pi- decays based on a 140 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one neutral B meson as a B0 --> pi+pi- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes Apipi = +0.58+/-0.15(stat)+/-0.07(syst) and Spipi = -1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, Apipi=Spipi=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any Spipi value.

The production of prompt $J/\ensuremath{\psi}$, $\ensuremath{\psi}(2S)$, ${\ensuremath{\chi}}_{c1}$, and ${\ensuremath{\chi}}_{c2}$ is studied using a $32.4{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected with the Belle detector at $\ensuremath{\Upsilon}(4S)$ and at $60\mathrm{MeV}$ below the resonance. The yield of prompt $J/\ensuremath{\psi}$ mesons in the $\ensuremath{\Upsilon}(4S)$ sample is compatible with that of continuum production; we set an upper limit $B(\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}J/\ensuremath{\psi}X)&lt;1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ at the $95%$ confidence level, and find $\ensuremath{\sigma}({e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}X)\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.47\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.13\mathrm{pb}$. The cross sections for prompt $\ensuremath{\psi}(2S)$ and direct $J/\ensuremath{\psi}$ are measured. The $J/\ensuremath{\psi}$ momentum spectrum, production angle distribution, and polarization are studied.

We present new measurements of CP-violation parameters in B0 -&gt; phiK0, K+K-Ks, f0(980)Ks, eta'Ks, omegaKs and Kspi0 decays based on a sample of 275 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the decay modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. The combined result for the B0-&gt;phiK0, K+K-Ks, f0(980)Ks, eta'Ks, omegaKs, Kspi0, and previously reported KsKsKs decays differs from the SM expectation by 2.4 standard deviations.

The angular distributions of the baryon-antibaryon low-mass enhancements seen in the charmless three-body baryonic B decays B+ -> p pbar K+, B0 -> p pbar Ks, and B0 -> p Lambdabar pi- are reported. A quark fragmentation interpretation is supported, while the gluonic resonance picture is disfavored. Searches for the Theta+ and Theta++ pentaquarks in the relevant decay modes and possible glueball states G with 2.2 GeV/c2 < M-ppbar < 2.4 GeV/c2 in the ppbar systems give null results. We set upper limits on the products of branching fractions, B(B0 -> Theta+ p)\times B(Theta+ -> p Ks) < 2.3 \times 10^{-7}, B(B+ -> Theta++ pbar) \times B(Theta++ -> p K+) < 9.1 \times 10^{-8}, and B(B+ -> G K+) \times B(G -> p pbar) < 4.1 \times 10^{-7} at the 90% confidence level. The analysis is based on a 140 fb^{-1} data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.

We have studied hadronic τ decay modes involving an η meson using 490 fb−1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. The following branching fractions have been measured: B(τ−→K−ηντ)=(1.58±0.05±0.09)×10−4, B(τ−→K−π0ηντ)=(4.6±1.1±0.4)×10−5, B(τ−→π−π0ηντ)=(1.35±0.03±0.07)×10−3, B(τ−→π−KS0ηντ)=(4.4±0.7±0.2)×10−5, and B(τ−→K∗−ηντ)=(1.34±0.12±0.09)×10−4. These results are substantially more precise than previous measurements. The new measurements are compared with theoretical calculations based on the CVC hypothesis or the chiral perturbation theory. We also set upper limits on branching fractions for τ decays into K−KS0ηντ, π−KS0π0ηντ, K−ηηντ, π−ηηντ and non-resonant K−π0ηντ final states.

The present work was undertaken to investigate chemical constituents and chemotaxonomic significance from the flowers of Cynanchum auriculatum Royle ex Wight (C. auriculatum) by phytochemical methods. As a result, sixteen compounds including phenols (1–7), flavonoids (8–13), and others (14–16) were yielded, and their chemical structures were elucidated by NMR and MS analyses, together with the comparison with the published spectroscopic data. Notably, seven compounds (3, 5, 6, 10, 12, 15, and 16) were first isolated from the family Apocynaceae; while five compounds (7, 9, 11, 13, and 14) were reported from C. auriculatum for the first time. Additionally, the chemotaxonomic significance of isolated compounds was also discussed.

We report the first observation of the charmless hyperonic B decay, B0-->pLambda(pi)(-), using a 78 fb(-1) data sample recorded on the Upsilon(4S) resonance with the Belle detector at KEKB. The measured branching fraction is B(B0-->pLambda(pi)(-))=(3.97(+1.00)(-0.80)+/-0.56)x10(-6). Searches for B0-->pLambda(K)- and pSigma(0)pi(-) yield no significant signals and we set 90% confidence-level upper limits of B(B0-->pLambda(K)-)<8.2x10(-7) and B(B0-->pSigma(0)pi(-))<3.8x10(-6).

We report results of a study of charmless B meson decays to three-body Kππ,KKπ and KKK final states. Measurements of branching fractions for B decays to K+(0)π+π−,K+K+K−,K0K+K−,K+K0SK0S and K0SK0SK0S final states are presented. The decays B0→K0K+K−,B+→K+K0SK0S and B0→K0SK0SK0S are observed for the first time. We also report evidence for B+→K+K−π+ decay. For the three-body final states K0K+π−,K0SK0Sπ+,K+K+π− and K−π+π+, 90% confidence level upper limits are reported. Finally, we discuss the possibility of using the three-body B0→K0SK+K− decay for CP violation studies. The results are obtained with a 78 fb−1 data sample collected at the Υ(4S) resonance by the Belle detector operating at the KEKB asymmetric energy e+e− collider.Received 1 August 2003DOI:https://doi.org/10.1103/PhysRevD.69.012001©2004 American Physical Society

CP violation in B → J/ψK * decays is studied using an angular analysis in a data sample of 253 fb -1 recorded with the Belle detector at the KEKB e + e -collider.The flavor separated measurements of the decay amplitudes indicate no evidence for direct CP violation.T-odd CP violation is studied using the asymmetries in triple product correlations, and the results are consistent with the Standard Model null predictions.The time-dependent angular analysis gives the following values of CP-violating parameters: sin 2φ 1 = 0.24 ± 0.31 ± 0.05 and cos 2φ 1 = 0.56 ± 0.79 ± 0.11.

We report the first measurement of the branching fraction for the inclusive decay B-->X(s)l(+)l(-), where l is either an electron or a muon, and X(s) is a hadronic recoil system that contains an s quark. We analyzed a data sample of 65.4 x 10(6) B meson pairs collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. We find B(B-->X(s)l(+)l(-))=[6.1 +/-1.4(stat) +1.4-1.1(syst)] x 10(-6) for dilepton masses greater than 0.2 GeV/c(2).

We report the observation of the radiative decay B+ --> K1(1270)+ gamma using a data sample of 140 fb-1 taken at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- collider. We find the branching fraction to be Br(B+ --> K1(1270)+ gamma) = (4.3 +- 0.9(stat.) +- 0.9(syst.)) x 10-5 with a statistical significance of 7.3sigma. We find no significant signal for B+ --> K1(1400)+ gamma and set an upper limit Br(B+ --> K1(1400)+ gamma) < 1.5 x 10-5 at the 90% confidence level. We also measure inclusive branching fractions for B+ --> K+ pi+ pi- gamma and B0 --> K0 pi+ pi- gamma in the mass range 1 GeV/c^2 < M(K+(0)pi+pi-) < 2 GeV/c^2.

We report measurements of CP violation parameters in B0→K0Sπ0γ transitions based on a data sample of 535×106B¯¯¯B pairs collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. One neutral B meson is fully reconstructed in the B0→K0Sπ0γ mode. The flavor of the accompanying B meson is identified from its decay products. We obtain time-dependent and direct CP violation parameters S and A for a K0Sπ0 invariant mass up to 1.8 GeV/c2 as SK0Sπ0γ=−0.10±0.31±0.07 and AK0Sπ0γ=−0.20±0.20±0.06. For a K0Sπ0 invariant mass near the K*0(892) resonance, we obtain SK*0γ=−0.32+0.36−0.33±0.05 and AK*0γ=−0.20±0.24±0.05.Received 10 November 2006DOI:https://doi.org/10.1103/PhysRevD.74.111104©2006 American Physical Society

We present a search for the rare decays B → h ( * ) νν, where h ( * ) stands for a light meson.A data sample of 535 million BB pairs collected with the Belle detector at the KEKB e + e -collider is used.Signal candidates are required to have an accompanying B meson fully reconstructed in a hadronic mode and signal-side particles consistent with a single h ( * ) meson.No significant signal is observed and we set upper limits on the branching fractions at 90% confidence level.The limits on B 0 → K * 0 νν and B + → K + νν decays are more stringent than the previous constraints, while the first searches for B 0 → K 0 νν, π 0 νν, ρ 0 νν, φνν and B + → K * + νν, ρ + νν are reported.

We report results of a Dalitz plot analysis of the three-body charmless B 0 → K 0 π + π -decay.The analysis is performed with a data sample that contains 388 million B B pairs collected near the Υ(4S) resonance with the Belle detector at the KEKB asymmetric energy e + e -collider.Measurements of branching fractions for the quasi-two-body decays B 0 → ρ(770) 0 K 0 , B 0 → f0(980)K 0 , B 0 → K * (892) + π -, B 0 → K * (1430) + π -, and upper limits on several other quasi-two-body decay modes are reported.

We study the characteristics of the low mass pp¯ enhancements near threshold in the three-body decays B+→pp¯K+ and B+→pp¯π+. We observe that the proton polar angle distributions in the pp¯ helicity frame in the two decays have the opposite polarity, and measure the forward-backward asymmetries as a function of the pp¯ mass for the pp¯K+ mode. We also search for the intermediate two-body decays, B+→p¯Δ++ and B+→pΔ¯0, and set upper limits on their branching fractions. These results are obtained from a 414fb−1 data sample that contains 449×106BB¯ events collected near the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider.

We report a new measurement of the time-dependent $CP$-violating parameters in ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decays with $535\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider operating at the $\ensuremath{\Upsilon}(4S)$ resonance. We find $1464\ifmmode\pm\else\textpm\fi{}65$ ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ events and measure the $CP$-violating parameters ${\mathcal{S}}_{\ensuremath{\pi}\ensuremath{\pi}}=\ensuremath{-}0.61\ifmmode\pm\else\textpm\fi{}0.10(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{syst})$ and ${\mathcal{A}}_{\ensuremath{\pi}\ensuremath{\pi}}=+0.55\ifmmode\pm\else\textpm\fi{}0.08(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{syst})$. We observe large direct $CP$ violation with a significance greater than 5 standard deviations for any ${\mathcal{S}}_{\ensuremath{\pi}\ensuremath{\pi}}$ value. Using isospin relations, we measure the Cabibbo-Kobayashi-Maskawa quark-mixing matrix angle ${\ensuremath{\phi}}_{2}=(97\ifmmode\pm\else\textpm\fi{}11)\ifmmode^\circ\else\textdegree\fi{}$ for the solution consistent with the standard model and exclude the range $11\ifmmode^\circ\else\textdegree\fi{}&lt;{\ensuremath{\phi}}_{2}&lt;79\ifmmode^\circ\else\textdegree\fi{}$ at the 95% confidence level.

We report a study of semileptonic $B$ decays to $P$-wave ${D}^{**}$ mesons. Semileptonic decay to a ${D}_{2}^{*}$ meson is observed for the first time and its product branching ratio is measured to be $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\overline{D}}_{2}^{*0}{\ensuremath{\ell}}^{+}\ensuremath{\nu})\ifmmode\times\else\texttimes\fi{}\mathcal{B}({\overline{D}}_{2}^{*0}\ensuremath{\rightarrow}{D}^{\ensuremath{-}}{\ensuremath{\pi}}^{+})=0.22\ifmmode\pm\else\textpm\fi{}0.03(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{syst}.)%$. The result is obtained using fully reconstructed $B$ tags from a data sample that contains $657\ifmmode\times\else\texttimes\fi{}{10}^{6}B\overline{B}$ pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider.

We report a measurement of CP violating asymmetries in B0(¯¯¯B0)→K+K−K0S decays with a time-dependent Dalitz approach. This analysis is based on a data sample of 657×106 B¯¯¯B pairs accumulated at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. As the result of an unbinned maximum likelihood fit to the selected candidates, the mixing-induced and direct CP violation parameters ϕeff1 and ACP are obtained for B0→ϕ(1020)K0S, B0→f0(980)K0S, and other B0→K+K−K0S decays. We find four solutions that describe the data. There are ϕeff1(B0→ϕ(1020)K0S)=(32.2±9.0±2.6±1.4)°;ϕeff1(B0→ϕ(1020)K0S)=(26.2±8.8±2.7±1.2)°;ϕeff1(B0→ϕ(1020)K0S)=(27.3±8.6±2.8±1.3)°;andϕeff1(B0→ϕ(1020)K0S)=(24.3±8.0±2.9±5.2)°. The values for the CP violating phase in B0→ϕ(1020)K0S are similar, but other properties of the Dalitz plot are quite different for the four solutions. These four solutions have consistent ϕeff1 values for all three B-meson decay channels and none of them deviates significantly from the values measured in B→(c¯c)K0 decays with the currently available statistics. In addition, we find no significant direct CP violation.Received 22 July 2010DOI:https://doi.org/10.1103/PhysRevD.82.073011© 2010 The American Physical Society

Little is currently known about long-term health effects of ambient ultrafine particles (UFPs) due to the lack of exposure assessment metrics suitable for use in large population-based studies. Land use regression (LUR) models have been used increasingly for modeling small-scale spatial variation in UFPs concentrations in European and American, but have never been applied in developing countries with heavy air pollution. This study developed a land-use regression (LUR) model for UFP exposure assessment in Shanghai, a typic mega city of China, where dense population resides. A 30-minute measurement of particle number concentrations of UFPs was collected at each visit at 144 fixed sites, and each was visited three times in each season of winter, spring, and summer. The annual adjusted average was calculated and regressed against pre-selected geographic information system-derived predictor variables using a stepwise variable selection method. The final LUR model explained 69% of the spatial variability in UFP with a root mean square error of 6008 particles cm−3. The 10-fold cross validation R2 reached 0.68, revealing the robustness of the model. The final predictors included traffic-related NOx emissions, number of restaurants, building footprint area, and distance to the nearest national road. These predictors were within a relatively small buffer size, ranging from 50 m to 100 m, indicating great spatial variations of UFP particle number concentration and the need of high-resolution models for UFP exposure assessment in urban areas. We concluded that based on a purpose-designed short-term monitoring network, LUR model can be applied to predict UFPs spatial surface in a mega city of China. Majority of the spatial variability in the annual mean of ambient UFP was explained in the model comprised primarily of traffic-, building-, and restaurant-related predictors.

We report measurements for two-body charmless hadronic B decays with an η′ meson in the final state. Using 11.1×106 BB̄ pairs collected with the Belle detector, we find BF(B+→η′K+)=(79+12−11±9)×10−6 and BF(B0→η′K0)=(55+19−16±8)×10−6, where the first and second errors are statistical and systematic, respectively. No signal is observed in the mode B+→η′π+, and we set a 90% confidence level upper limit of BF(B+→η′π+)<7×10−6. The CP asymmetry in B±→η′K± decays is investigated and a limit at 90% confidence level of −0.20<ACP<0.32 is obtained.

We report the first observation of the charmless hyperonic $B$ decay, ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\Lambda}\overline{\ensuremath{\Lambda}}{K}^{+}$, using a $140\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample recorded at the $\ensuremath{\Upsilon}(4\mathrm{S})$ resonance with the Belle detector at the KEKB ${e}^{+}{e}^{\ensuremath{-}}$ collider. The measured branching fraction is $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}\ensuremath{\Lambda}\overline{\ensuremath{\Lambda}}{K}^{+})=({2.91}_{\ensuremath{-}0.70}^{+0.90}\ifmmode\pm\else\textpm\fi{}0.38)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. We also perform a search for the related decay mode ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\Lambda}\overline{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{+}$, but do not find a significant signal. We set a 90% confidence-level upper limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}\ensuremath{\Lambda}\overline{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{+})&lt;2.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$.

The branching fractions and the decay amplitudes of B→J/ψK∗ decays are measured in a 29.4 fb−1 data sample collected with the Belle detector at the KEKB electron–positron collider. The decay amplitudes of helicity states of the J/ψK∗ system are determined from the full angular distribution of the final state particles in the transversity basis. The branching fractions are measured to be (1.29±0.05±0.13)×10−3 for neutral mesons and (1.28±0.07±0.14)×10−3 for charged mesons. The measured longitudinal and transverse (perpendicular to the transversity plane) amplitudes are |A0|2=0.62±0.02±0.03 and |A⊥|2=0.19±0.02±0.03, respectively. The value of |A⊥|2 shows that the CP even component dominates in the B0→J/ψK∗0(KSπ0) decay.

This article describes an observation of mixing-induced $\mathrm{CP}$ violation and a measurement of the $\mathrm{CP}$ violation parameter, $\mathrm{sin}2{\ensuremath{\varphi}}_{1},$ with the Belle detector at the KEKB asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. Using a data sample of $29.1 {\mathrm{fb}}^{\ensuremath{-}1}$ recorded on the $\ensuremath{\Upsilon}(4S)$ resonance that contains 31.3 million $B\overline{B}$ pairs, we reconstruct decays of neutral B mesons to the following $\mathrm{CP}$ eigenstates: $J/\ensuremath{\psi}{K}_{S}^{0},$ $\ensuremath{\psi}{(2S)K}_{S}^{0},$ ${\ensuremath{\chi}}_{c1}{K}_{S}^{0},$ ${\ensuremath{\eta}}_{c}{K}_{S}^{0},$ $J/\ensuremath{\psi}{K}_{L}^{0}$ and $J/\ensuremath{\psi}{K}^{*0}.$ The flavor of the accompanying B meson is identified by combining information from primary and secondary leptons, ${K}^{\ifmmode\pm\else\textpm\fi{}}$ mesons, $\ensuremath{\Lambda}$ baryons, slow and fast pions. The proper-time interval between the two B meson decays is determined from the distance between the two decay vertices measured with a silicon vertex detector. The result $\mathrm{sin}2{\ensuremath{\varphi}}_{1}=0.99\ifmmode\pm\else\textpm\fi{}0.14(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{syst})$ is obtained by applying a maximum likelihood fit to the 1137 candidate events. We conclude that there is large $\mathrm{CP}$ violation in the neutral B meson system. A zero value for $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ is ruled out by more than six standard deviations.

We present a measurement of the branching fraction for the semileptonic B decay B̄0→D+ℓ−ν̄, where ℓ− can be either an electron or a muon. We find Γ(B̄0→D+ℓ−ν̄)=(13.79±0.76±2.51) ns−1, and the resulting branching fraction B(B̄0→D+ℓ−ν̄)=(2.13±0.12±0.39)%, where the first error is statistical and the second systematic. We also investigate the B̄0→D+ℓ−ν̄ form factor and the implications of the result for |Vcb|. From a fit to the differential decay distribution we obtain the rate normalization |Vcb|FD(1)=(4.11±0.44±0.52)×10−2. Using a theoretical calculation of FD(1), the Cabibbo–Kobayashi–Maskawa matrix element |Vcb|=(4.19±0.45±0.53±0.30)×10−2 is obtained, where the last error comes from the theoretical uncertainty of FD(1). The results are based on a data sample of 10.2fb−1 recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e+e− collider.

We have measured the branching fraction B, longitudinal polarization fraction f L , and CP asymmetry coefficients A and S for B 0 → ρ + ρ -decays with the Belle detector at the KEKB e + e -collider using 253 fb -1 of data.We obtain B = 22.8 ± 3.8 (stat) +2.3 -2.6 (syst) × 10 -6 , f L = 0.941 +0.034 -0.040 (stat) ± 0.030 (syst), A = 0.00 ± 0.30 (stat) ± 0.09 (syst), and S = 0.08 ± 0.41 (stat) ± 0.09 (syst).These values are used to constrain the Cabibbo-Kobayashi-Maskawa phase φ 2 ; the solution consistent with the Standard Model is φ 2 = (88 ± 17) • or 59 • < φ 2 < 115 • at 90% C.L.

We report the observation of the flavor-changing neutral current process b --&gt; d gamma using a sample of 386*10^6 B meson pairs accumulated by the Belle detector at the KEKB e+ e- collider. We measure branching fractions for the exclusive modes B- --&gt; rho- gamma, B0bar --&gt; rho0 gammaand B0bar --&gt; omega gamma. Assuming that these three modes are related by isospin, we find Br(B --&gt; (rho,omega) gamma) = (1.32 +0.34-0.31(stat.) +0.10-0.09(syst.)) * 10^-6 with a significance of 5.1 sigma. This result is used to determine the ratio of CKM matrix elements |V_td/V_ts| to be 0.199 +0.026-0.025(exp.) +0.018-0.015(theo.).

We report a measurement of the inclusive electron energy spectrum for charmed semileptonic decays of $B$ mesons in a $140\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We determine the first four moments of the electron energy spectrum for threshold values of the electron energy between 0.4 and 2.0 GeV. In addition, we provide values of the partial branching fraction (zeroth moment) for the same electron threshold energies, and independent measurements of the ${B}^{+}$ and ${B}^{0}$ partial branching fractions at 0.4 GeV and 0.6 GeV electron threshold energies. We measure the independent ${B}^{+}$ and ${B}^{0}$ partial branching fractions with electron threshold energies of 0.4 GeV to be $\ensuremath{\Delta}\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{X}_{c}e\ensuremath{\nu})=(10.79\ifmmode\pm\else\textpm\fi{}0.25(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.27(\mathrm{sys}.))%$ and $\ensuremath{\Delta}\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{X}_{c}e\ensuremath{\nu})=(10.08\ifmmode\pm\else\textpm\fi{}0.30(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.22(\mathrm{sys}.))%$. Full correlations between all measurements are evaluated.

Characteristics of microjet methane diffusion flames stabilized on top of the vertically oriented, stainless-steel tubes with an inner diameter ranging from 186 to 778 μ m are investigated experimentally, theoretically and numerically. Of particular interest are the flame shape, flame length and quenching limit, as they may be related to the minimum size and power of the devices in which such flames would be used for future micro-power generation. Experimental measurements of the flame shape, flame length and quenching velocity are compared with theoretical predictions as well as detailed numerical simulations. Comparisons of the theoretical predictions with measured results show that only Roper's model can satisfactorily predict the flame height and quenching velocity of microjet methane flames. Detailed numerical simulations, using skeletal chemical kinetic mechanism, of the flames stabilized at the tip of d = 186, 324 and 529 μ m tubes are performed to investigate the flame structures and the effects of burner materials on the standoff distance near extinction limit. The computed flame shape and flame length for the d = 186 μm flame are in excellent agreement with experimental results. Numerical predictions of the flame structures strongly suggest that the flame burns in a diffusion mode near the extinction limit. The calculated OH mass fraction isopleths indicate that different tube materials have a minor effect on the standoff distance, but influence the quenching gap between the flame and the tube.

The neutral $B$ meson pair produced at the $\ensuremath{\Upsilon}(4S)$ should exhibit a nonlocal correlation of the type discussed by Einstein, Podolsky, and Rosen. We measure this correlation using the time-dependent flavor asymmetry of semileptonic ${B}^{0}$ decays, which we compare with predictions from quantum mechanics and two local realistic models. The data are consistent with quantum mechanics, and inconsistent with the other models. Assuming that some $B$ pairs disentangle to produce ${B}^{0}$ and ${\overline{B}}^{0}$ with definite flavor, we find a decoherent fraction of $0.029\ifmmode\pm\else\textpm\fi{}0.057$, consistent with no decoherence.

We report the results of a study of neutral $B$ meson decays to the ${D}^{0}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ final state, where the ${D}^{0}$ is fully reconstructed. The results are obtained from an event sample containing $388\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$-meson pairs collected in the Belle experiment at the KEKB ${e}^{+}{e}^{\ensuremath{-}}$ collider. The total branching fraction of the three-body decay $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(8.4\ifmmode\pm\else\textpm\fi{}0.4(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.8(\mathrm{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ has been measured. The intermediate resonant structure of these three-body decays has been studied. From a Dalitz plot analysis we have obtained the product of the branching fractions for ${D}_{2}^{*+}$ and ${D}_{0}^{*+}$ production: $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}_{2}^{*+}{\ensuremath{\pi}}^{\ensuremath{-}})\ifmmode\times\else\texttimes\fi{}\mathcal{B}({D}_{2}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+})=(2.15\ifmmode\pm\else\textpm\fi{}0.17(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.29(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.12(\mathrm{mod}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, and $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}_{0}^{*+}{\ensuremath{\pi}}^{\ensuremath{-}})\ifmmode\times\else\texttimes\fi{}\mathcal{B}({D}_{0}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+})=(0.60\ifmmode\pm\else\textpm\fi{}0.13(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.15(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.22(\mathrm{mod}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. This is the first observation of the ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}_{0}^{*+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay. The ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\rho}}^{0}$ and ${D}^{0}{f}_{2}$ branching fractions are measured to be: $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\rho}}^{0})=(3.19\ifmmode\pm\else\textpm\fi{}0.20(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.24(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.38(\mathrm{mod}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, and $\mathcal{B}({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{0}{f}_{2})=(1.20\ifmmode\pm\else\textpm\fi{}0.18(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.21(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.32(\mathrm{mod}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$.

The inclusive production of $D_s$, $D^0$, and $J/\psi$ mesons is studied using a 1.86 fb$^{-1}$ data sample collected on the $\Upsilon$(5S) resonance by the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider. The number of $b\bar{b}$ events in the $\Upsilon$(5S) data sample is determined. We measure the branching fractions $B(\Upsilon({\rm 5S}) \to D_s X) / 2 = (23.6 \pm 1.2 \pm 3.6)%$, $B(\Upsilon({\rm 5S}) \to D^0 X) / 2 = (53.8 \pm 2.0 \pm 3.4)%$}, and $B(\Upsilon({\rm 5S}) \to J/\psi X) / 2 = (1.030 \pm 0.080 \pm 0.067)%$. From the $D_s$ and $D^0$ inclusive branching fractions the ratio $f_s = (18.0 \pm 1.3 \pm 3.2)%$} of $B_s^{(*)} \bar{B}_s^{(*)}$ to the total $b\bar{b}$ quark pair production at the $\Upsilon$(5S) energy is obtained in a model-dependent way.