A. Bornheim

Using 13.5 ${\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ annihilation data collected with the CLEO II detector, we have observed a narrow resonance decaying to ${D}_{s}^{*+}{\ensuremath{\pi}}^{0}$ with a mass near $2.46\mathrm{GeV}{/c}^{2}.$ The search for such a state was motivated by the recent discovery by the BaBar Collaboration of a narrow state at $2.32\mathrm{GeV}{/c}^{2},$ the ${D}_{\mathrm{sJ}}^{*}{(2317)}^{+},$ that decays to ${D}_{s}^{+}{\ensuremath{\pi}}^{0}.$ Reconstructing the ${D}_{s}^{+}{\ensuremath{\pi}}^{0}$ and ${D}_{s}^{*+}{\ensuremath{\pi}}^{0}$ final states in CLEO data, we observe peaks in both of the corresponding reconstructed mass difference distributions, $\ensuremath{\Delta}{M(D}_{s}{\ensuremath{\pi}}^{0}{)=M(D}_{s}{\ensuremath{\pi}}^{0})\ensuremath{-}{M(D}_{s})$ and $\ensuremath{\Delta}{M(D}_{s}^{*}{\ensuremath{\pi}}^{0}{)=M(D}_{s}^{*}{\ensuremath{\pi}}^{0})\ensuremath{-}{M(D}_{s}^{*}),$ both of them at values near $350\mathrm{MeV}{/c}^{2}.$ We interpret these peaks as signatures of two distinct states, the ${D}_{\mathrm{sJ}}^{*}{(2317)}^{+}$ plus a new state, designated as the ${D}_{\mathrm{sJ}}{(2463)}^{+}.$ Because of the similar $\ensuremath{\Delta}M$ values, each of these states represents a source of background for the other if photons are lost, ignored or added. A quantitative accounting of these reflections confirms that both states exist. We have measured the mean mass differences $〈\ensuremath{\Delta}{M(D}_{s}{\ensuremath{\pi}}^{0})〉=350.0\ifmmode\pm\else\textpm\fi{}1.2(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.0(\mathrm{syst})\mathrm{MeV}{/c}^{2}$ for the ${D}_{\mathrm{sJ}}^{*}{(2317)}^{+}$ state, and $〈\ensuremath{\Delta}{M(D}_{s}^{*}{\ensuremath{\pi}}^{0})〉=351.2\ifmmode\pm\else\textpm\fi{}1.7(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.0(\mathrm{syst})\mathrm{MeV}{/c}^{2}$ for the new ${D}_{\mathrm{sJ}}{(2463)}^{+}$ state. We have also searched, but find no evidence, for decays of the two states via the channels ${D}_{s}^{*+}\ensuremath{\gamma},{D}_{s}^{+}\ensuremath{\gamma},$ and ${D}_{s}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}.$ The observations of the two states at 2.32 and $2.46\mathrm{GeV}{/c}^{2},$ in the ${D}_{s}^{+}{\ensuremath{\pi}}^{0}$ and ${D}_{s}^{*+}{\ensuremath{\pi}}^{0}$ decay channels, respectively, are consistent with their interpretations as $c\overline{s}$ mesons with an orbital angular momentum $L=1$ and spin and parity ${J}^{P}{=0}^{+}$ and ${1}^{+}.$

We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, <E( gamma)> = 2.346+/-0.032+/-0.011 GeV, and <E(2)(gamma)>-<E(gamma)>(2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.

A measurement of the proton structure function F_2(x,Q^2) is presented in the kinematic range 0.045 GeV^2 < Q^2 < 0.65 GeV^2 and 6*10^{-7} < x < 1*10^{-3}. The results were obtained using a data sample corresponding to an integrated luminosity of 3.9pb^-1 in e^+p reactions recorded with the ZEUS detector at HERA. Information from a silicon-strip tracking detector, installed in front of the small electromagnetic calorimeter used to measure the energy of the final-state positron at small scattering angles, together with an enhanced simulation of the hadronic final state, has permitted the extension of the kinematic range beyond that of previous measurements. The uncertainties in F_2 are typically less than 4%. At the low Q^2 values of the present measurement, the rise of F_2 at low x is slower than observed in HERA data at higher Q^2 and can be described by Regge theory with a constant logarithmic slope. The dependence of F_2 on Q^2 is stronger than at higher Q^2 values, approaching, at the lowest Q^2 values of this measurement, a region where F_2 becomes nearly proportional to Q^2.

We present the first measurement of the D*+ width using 9/fb of e+ e- data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D*+ -> D0 pi+ decay. We find Gamma(D*+) = 96 +- 4 (Statistical) +- 22 (Systematic) keV. We also measure the energy release in the decay and compute Delta m = m(D*+) - m(D0) = 145.412 +- 0.002 (Statistical) +- 0.012 (Systematic) MeV/c^2

A small electromagnetic sampling calorimeter, installed in the ZEUS experiment in 1995, significantly enhanced the acceptance for very low x and low Q^2 inelastic neutral current scattering, e^{+}p \to e^{+}X, at HERA. A measurement of the proton structure function F_2 and the total virtual photon-proton (\gamma^*p) cross-section is presented for 0.11 \le Q^{2} \le 0.65 GeV^2 and 2 \times 10^{-6} \le x \le 6 \times 10^{-5}, corresponding to a range in the \gamma^{*}p c.m. energy of 100 \le W \le 230 GeV. Comparisons with various models are also presented.

We use data collected with the CLEO II detector to perform a high-statistics measurement of the resonant substructure in ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}$ decays. We find that the Dalitz plot is well represented by a combination of seven quasi-two-body decay channels $[{K}^{*0}{\ensuremath{\pi}}^{0},{K}^{\ensuremath{-}}\ensuremath{\rho},{K}^{*\ensuremath{-}}{\ensuremath{\pi}}^{+},{K}_{0}{(1430)}^{\ensuremath{-}}{\ensuremath{\pi}}^{+},{K}_{0}{(1430)}^{0}{\ensuremath{\pi}}^{0},{K}^{\ensuremath{-}}{\ensuremath{\rho}}^{+}(1700),$ and ${K}^{*}{(1680)}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}],$ plus a small non-resonant component. We see no evidence of a scalar $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\kappa}}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ resonance in the mass range recently reported by other groups. Using the amplitudes and phases from this analysis, we calculate an integrated $\mathrm{CP}$ asymmetry of $\ensuremath{-}0.031\ifmmode\pm\else\textpm\fi{}0.086.$

Using $20.7\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ annihilation data taken at $\sqrt{s}=3.671\text{ }\text{ }\mathrm{GeV}$ with the $\mathrm{CLEO}\mathrm{\text{\ensuremath{-}}}c$ detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfer of $|{Q}^{2}|=13.48\text{ }\text{ }{\mathrm{GeV}}^{2}$ by the reaction ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}^{+}{h}^{\ensuremath{-}}$. The measurements are the first ever with identified pions and kaons of $|{Q}^{2}|&gt;4\text{ }\text{ }{\mathrm{GeV}}^{2}$, with the results ${F}_{\ensuremath{\pi}}(13.48\text{ }\text{ }{\mathrm{GeV}}^{2})=0.075\ifmmode\pm\else\textpm\fi{}0.008(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.005(\mathrm{syst})$ and ${F}_{K}(13.48\text{ }\text{ }{\mathrm{GeV}}^{2})=0.063\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.001(\mathrm{syst})$. The result for the proton, assuming ${G}_{E}^{p}={G}_{M}^{p}$, is ${G}_{M}^{p}(13.48\text{ }\text{ }{\mathrm{GeV}}^{2})=0.014\ifmmode\pm\else\textpm\fi{}0.002(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.001(\mathrm{syst})$, which is in agreement with earlier results.

We present the first measurement of the D*(+) width using 9/fb of e(+)e(-) data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the Cornell Electron-positron Storage Ring beam spot to measure the energy release distribution from the D*(+)-->D(0)pi(+) decay. We find gamma(D*(+)) = 96+/-4 (stat)+/-22 (syst) keV. We also measure the energy release in the decay and compute Delta m identical with m(D*(+))-m(D(0)) = 145.412+/-0.002 (stat)+/-0.012 (syst) MeV/c(2).

In e(+)e(-) collisions using the CLEO detector, we have studied the decay of the D0 to the final state K(0)(S)pi(+)pi(-) with the initial flavor of the D0 tagged by the decay D(*+)-->D0pi(+). We use the Dalitz technique to measure the resonant substructure in this final state and clearly observe ten different contributions by fitting for their amplitudes and relative phases. We observe a K(*)(892)(+)pi(-) component which arises from doubly Cabibbo suppressed decays or D0-D0; mixing.

The photoproduction reaction gamma p -> mu+ mu- p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb^{-1}. The Upsilon meson has been observed in photoproduction for the first time. The sum of the products of the elastic Upsilon(1S), Upsilon(2S), Upsilon(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 +- 6.0(stat.)^{+2.7}_{-2.3}(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model.

This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel $D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ $ (+ c.c.) has been used in the study. The $e^+p$ cross section for inclusive D^{*\pm} production with $5<Q^2<100 GeV^2$ and $y<0.7$ is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {$1.3<p_T(D^{*\pm})<9.0$ GeV and $| \eta(D^{*\pm}) |<1.5$}. Differential cross sections as functions of p_T(D^{*\pm}), $\eta(D^{*\pm}), W$ and $Q^2$ are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and $\eta$(D^{*\pm}), the charm contribution $F_2^{c\bar{c}}(x,Q^2)$ to the proton structure function is determined for Bjorken $x$ between 2 $\cdot$ 10$^{-4}$ and 5 $\cdot$ 10$^{-3}$.

We report on the observation of the ηc′(2S01), the radial excitation of the ηc(1S01) ground state of charmonium, in the two-photon fusion reaction γγ→ηc′→KS0K±π∓ in 13.6 fb−1 of CLEO II/II.V data and 13.1 fb−1 of CLEO III data. We obtain M(ηc′)=3642.9±3.1(stat)±1.5(syst) MeV and M(ηc)=2981.8±1.3(stat)±1.5(syst) MeV. The corresponding values of hyperfine splittings between S01 and S13 states are ΔMhf(1S)=115.1±2.0 MeV and ΔMhf(2S)=43.1±3.4 MeV. Assuming that the ηc and ηc′ have equal branching fractions to KSKπ, we obtain Γγγ(ηc′)=1.3±0.6 keV.Received 23 December 2003DOI:https://doi.org/10.1103/PhysRevLett.92.142001©2004 American Physical Society

We present final measurements of 13 charmless hadronic B decay modes from the CLEO experiment. The decay modes include the ten ππ, Kπ, and KK final states and new limits on dibaryonic final states, p¯p, p¯Λ, and Λ¯Λ, as well as a new determination of the ratio B(→BDK)/B(→BDπ). The results are based on the full CLEO II and CLEO III data samples totalling 15.3fb−1 at the Υ(4S), and supercede previously published results.Received 13 February 2003Corrected 6 June 2007DOI:https://doi.org/10.1103/PhysRevD.68.052002©2003 American Physical Society

We have measured the first and second moments of the hadronic mass-squared distribution in B -> X_c l nu, for P(lepton) > 1.5 GeV/c. We find <M_X^2 - M_D[Bar]^2> = 0.251 +- 0.066 GeV^2, < (M_X^2 -<M_X^2>)^2 > = 0.576 +- 0.170 GeV^4, where M_D[Bar] is the spin-averaged D meson mass. From that first moment and the first moment of the photon energy spectrum in b -> s gamma, we find the HQET parameter lambda_1 (MS[Bar], to order 1/M^3 and beta_0 alpha_s^2) to be -0.24 +- 0.11 GeV^2. Using these first moments and the B semileptonic width, and assuming parton-hadron duality, we obtain |V_cb| = 0.0404 +- 0.0013.

We report on determinations of $|{V}_{\mathrm{ub}}|$ resulting from studies of the branching fraction and ${q}^{2}$ distributions in exclusive semileptonic B decays that proceed via the $\stackrel{\ensuremath{\rightarrow}}{b}u$ transition. Our data set consists of the $9.7\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ meson pairs collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the CLEO II detector. We measure $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\mathcal{l}}^{+}\ensuremath{\nu})=(1.33\ifmmode\pm\else\textpm\fi{}0.18\ifmmode\pm\else\textpm\fi{}0.11\ifmmode\pm\else\textpm\fi{}0.01\ifmmode\pm\else\textpm\fi{}0.07)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{\ensuremath{-}}{\mathcal{l}}^{+}\ensuremath{\nu})=(2.17\ifmmode\pm\else\textpm\fi{}{0.34}_{\ensuremath{-}0.54}^{+0.47}\ifmmode\pm\else\textpm\fi{}0.41\ifmmode\pm\else\textpm\fi{}0.01)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4},$ where the errors are statistical, experimental systematic, systematic due to residual form-factor uncertainties in the signal, and systematic due to residual form-factor uncertainties in the cross-feed modes, respectively. We also find $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{\mathcal{l}}^{+}\ensuremath{\nu})=(0.84\ifmmode\pm\else\textpm\fi{}0.31\ifmmode\pm\else\textpm\fi{}0.16\ifmmode\pm\else\textpm\fi{}0.09)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4},$ consistent with what is expected from the $\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\pi}\mathcal{l}\ensuremath{\nu}$ mode and quark model symmetries. We extract $|{V}_{\mathrm{ub}}|$ using light-cone sum rules for $0&lt;~{q}^{2}&lt;16{\mathrm{GeV}}^{2}$ and lattice QCD for $16{\mathrm{GeV}}^{2}&lt;~{q}^{2}&lt;{q}_{\mathrm{max}}^{2}.$ Combining both intervals yields $|{V}_{\mathrm{ub}}|=(3.24\ifmmode\pm\else\textpm\fi{}0.22\ifmmode\pm\else\textpm\fi{}{0.13}_{\ensuremath{-}0.39}^{+0.55}\ifmmode\pm\else\textpm\fi{}0.09)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ for $\ensuremath{\pi}\mathcal{l}\ensuremath{\nu},$ and $|{V}_{\mathrm{ub}}|=(3.00\ifmmode\pm\else\textpm\fi{}{0.21}_{\ensuremath{-}0.35\ensuremath{-}0.38}^{+0.29+0.49}\ifmmode\pm\else\textpm\fi{}0.28)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ for $\ensuremath{\rho}\mathcal{l}\ensuremath{\nu},$ where the errors are statistical, experimental systematic, theoretical, and \ensuremath{\rho}l\ensuremath{\nu} form-factor shape, respectively. Our combined value from both decay modes is $|{V}_{\mathrm{ub}}|=(3.17\ifmmode\pm\else\textpm\fi{}{0.17}_{\ensuremath{-}0.17\ensuremath{-}0.39}^{+0.16+0.53}\ifmmode\pm\else\textpm\fi{}0.03)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}.$

We report a new measurement of the CKM parameter V_ub made with a sample of 9.7 million B B-bar events collected with the CLEO II detector. Using Heavy Quark theory, we combine the observed yield of leptons from semileptonic B decay in the end-point momentum interval 2.2-2.6 GeV/c with recent CLEO II data on B --> X_s gamma to find |V_ub| = (4.08 +/- 0.34 +/- 0.44 +/- 0.16 +/- 0.24) x 10^-3, where the first two uncertainties are experimental and the last two are from theory.

The resonant substructure in D0 --> K0S pi+ pi- decays is described by a combination of ten quasi two-body intermediate states which include both CP-even and CP-odd eigenstates and one doubly-Cabibbo suppressed channel. We present a formalism that connects the variation in D0 decay time over the Dalitz plot with the mixing parameters, x and y, that describe off-shell and on-shell D0-D0B mixing. We analyze the CLEO II.V data sample and find the parameters x and y are consistent with zero. We limit (-4.7 < x < 8.6)% and (-6.1 < y < 3.5)% at the 95\% confidence level

We report on the multiple wavelength laser monitoring system designed for the compact muon solenoid (CMS) lead tungstate crystal calorimeter. Results are presented for the test-beam performance of the system designed to achieve ⩽0.2% relative optical transmittance inter-calibration for 75 848 lead tungstate crystals. The system cycles continuously over the calorimeter to follow each crystal's evolution under the irradiation and recovery periods foreseen during operation at the LHC.

Using data obtained with the CLEO III detector, running at the Cornell Electron Storage Ring (CESR), we report on a new study of exclusive radiative $\ensuremath{\Upsilon}(1\mathrm{S})$ decays into the final states $\ensuremath{\gamma}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, $\ensuremath{\gamma}{K}^{+}{K}^{\ensuremath{-}}$, and $\ensuremath{\gamma}p\overline{p}$. We present branching ratio measurements for the decay modes $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}{f}_{2}(1270)$, $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}{f}_{2}^{\ensuremath{'}}(1525)$, and $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}{K}^{+}{K}^{\ensuremath{-}}$; helicity production ratios for ${f}_{2}(1270)$ and ${f}_{2}^{\ensuremath{'}}(1525)$; upper limits for the decay $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}{f}_{J}(2200)$, with ${f}_{J}(2220)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, ${K}^{+}{K}^{\ensuremath{-}}$, $p\overline{p}$; and an upper limit for the decay $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}X(1860)$, with $X(1860)\ensuremath{\rightarrow}\ensuremath{\gamma}p\overline{p}$.

High energy particle collider experiments are facing ever more challenging conditions, operating at todays accelerators capable of providing instantaneous luminosities of 10 34 cm -2 s -1 and above.The high center of mass energy, the large number of simultaneous collision of beam particles in the experiments and the very high repetition rates of the collision events pose huge challenges.They result in extremely high particle fluxes, causing very high occupancies in the particle physics detectors operating at these machines.A precise timing information with a precision of around 10 ps and below is seen as a major aid in the reconstruction of the physics events under such challenging conditions.In this paper I discuss applications of precision timing in high pile-up conditions and review the efforts of the LHC collaborations to augment the timing performance of their detectors during future upgrade campaigns.Different detector technologies allowing precision timing measurements will be discussed and their potential benefit for a holistic event reconstruction will be illustrated.

We present the first evidence for the production of $\ensuremath{\Upsilon}(1D)$ states in the four-photon cascade, $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b}(2P),$ ${\ensuremath{\chi}}_{b}(2P)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\Upsilon}(1D),$ $\ensuremath{\Upsilon}(1D)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b}(1P),$ ${\ensuremath{\chi}}_{b}(1P)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\Upsilon}(1S),$ followed by the $\ensuremath{\Upsilon}(1S)$ annihilation into ${e}^{+}{e}^{\ensuremath{-}}$ or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}.$ The signal has a significance of 10.2 standard deviations. The measured product branching ratio for these five decays, $(2.5\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5},$ is consistent with the theoretical estimates. The data are dominated by the production of one $\ensuremath{\Upsilon}(1D)$ state consistent with the $J=2$ assignment. Its mass is determined to be $(10161.1\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}1.6)$ MeV, which is consistent with the predictions from potential models and lattice QCD calculations. We also searched for $\ensuremath{\Upsilon}(3S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{b}(2P),$ ${\ensuremath{\chi}}_{b}(2P)\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\Upsilon}(1D),$ followed by either $\ensuremath{\Upsilon}(1D)\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\Upsilon}(1S)$ or $\ensuremath{\Upsilon}(1D)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\Upsilon}(1S).$ We find no evidence for such decays and set upper limits on the product branching ratios.

This paper presents the first analysis of diffractive photon dissociation events in deep inelastic positron-proton scattering at HERA in which the proton in the final state is detected and its momentum measured. The events are selected by requiring a scattered proton in the ZEUS leading proton spectrometer (LPS) with χ L > 0.97, where xL is the fraction of the incoming proton beam momentum carried by the scattered proton. The use of the LPS significantly reduces the contamination from events with diffractive dissociation of the proton into low mass states and allows a direct measurement of t, the square of the four-momentum exchanged at the proton vertex. The dependence of the cross section ont is measured in the interval 0.073 < |t| < 0.4 GeV2 and is found to be described by an exponential shape with the slope parameterb = 7.2 ± 1.1(stat.) −0.9 +0.7 (syst.) GeV−2. The diffractive structure function FD (4) is presented as 0.9 a function of χ H ≃ 1 − χ L and β, the momentum fraction of the struck quark with respect to χ H , and averaged over thet interval 0.073 < |t′ < 0.4 GeV2 and the photon virtuality range 5 <Q 2 < 20 GeV2. In the kinematic range 4 × 104 < χ p < 0.03 and 0.015 < β < 0.5, the χ p dependence ofF D(4) is fitted with a form (1/χ p )α , yieldinga − 1.00 ± 0.09 (stat.) −0.05 +0.11 (syst.). Upon integration overL, the structure functionF 2 D(3) is determined in a kinematic range extending to higher χ p and lower β compared to our previous analysis; the results are discussed within the framework of Regge theory.

Using the CLEO detector at the Cornell Electron-positron Storage Ring, we have measured the scaled momentum spectra, $d\ensuremath{\sigma}/d{x}_{p}$, and the inclusive production cross sections of the charm mesons ${D}^{+}$, ${D}^{0}$, ${D}^{\ensuremath{\star}+}$, and ${D}^{\ensuremath{\star}0}$ in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at about 10.5 GeV center of mass energy, excluding the decay products of $B$ mesons. The statistical accuracy and momentum resolution are superior to previous measurements at this energy.

We describe several measurements using the decays D 0 → K + K -and π + π -.We find the ratio of partial widths, Γ D 0 → K + K -/Γ D 0 → π + π -, to be 2.96 ± 0.16 ± 0.15, where the first error is statistical and the second is systematic.We observe no evidence for direct CP violation, obtaining A CP (KK) = (0.0 ± 2.2 ± 0.8)% and A CP (ππ) = (1.9 ± 3.2 ± 0.8)%.In the limit of no CP violation we measure the mixing parameter y CP = -0.012± 0.025 ± 0.

The exclusive electroproduction of omega mesons, ep -> e omega p, has been studied in the kinematic range 3<Q^2<20 GeV^2, 40<W<120 GeV and |t|<0.6 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 37.7 pb^{-1}. The omega mesons were identified via the decay omega -> pi^+pi^-pi^0. The exclusive (ep -> e omega p) cross section in the above kinematic region is 0.108 +- 0.014(stat.) +- 0.026(syst.) nb. The reaction ep -> e phi p, phi -> pi^+pi^-pi^0, has also been measured. The cross sections, as well as the cross-section ratios omega/rho and omega/phi, are presented as a function of W and Q^2. Thus, for the first time, the properties of omega electroproduction can be compared to those of rho^0, phi and J/psi electroproduction at high W.

We have studied the inclusive photon spectra in Upsilon(2S) and Υ(3S) decays using a large statistics data sample obtained with the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates and photon energies for Upsilon(2S)-&gt;gamma chi_bJ(1P) and Upsilon(3S)-&gt;gamma chi_bJ(2P) J=0,1,2. We measure the rate for a rare E1 transition Upsilon(3S)-&gt;gamma chi_b0(1P) for the first time. We also set upper limits on the rates for the hindered magnetic dipole (M1) transitions to the eta_b(1S) and eta_b(2S) states.

The amplitude of the signal collected from the PbWO4 crystals of the CMS electromagnetic calorimeter is reconstructed by a digital filtering technique. The amplitude reconstruction has been studied with test beam data recorded from a fully equipped barrel supermodule. Issues specific to data taken in the test beam are investigated, and the implementation of the method for CMS data taking is discussed.

We investigate the decays D(0)-->pi(-)l(+)nu and D(0)-->K(-)l(+)nu, where l is e or mu, using approximately 7 fb(-1) of data collected with the CLEO III detector. We find R(0) identical with B(D(0)-->pi(-)e(+)nu)/B(D(0)-->K(-)e(+)nu)=0.082+/-0.006+/-0.005. Fits to the kinematic distributions of the data provide parameters describing the form factor of each mode. Combining the form factor results and R(0) gives |f(pi)(+)(0)|(2)|V(cd)|(2)/|f(K)(+)(0)|(2)|V(cs)|(2)=0.038(+0.006+0.005)(-0.007-0.003).

The High Luminosity phase of the Large Hadron Collider will deliver 10 times more integrated luminosity than the existing collider, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry. As part of its upgrade program, the Compact Muon Solenoid collaboration is designing a high-granularity calorimeter (HGCAL) to replace the existing endcap calorimeters. It will feature unprecedented transverse and longitudinal readout and triggering segmentation for both electromagnetic and hadronic sections. The electromagnetic section and a large fraction of the hadronic section will be based on hexagonal silicon sensors of 0.5–1 cm2 cell size, with the remainder of the hadronic section being based on highly-segmented scintillators with silicon photomultiplier readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. First hexagonal silicon modules, using the existing Skiroc2 front-end ASIC developed for CALICE, have been tested in beams at Fermilab and CERN in 2016. We present results from these tests, in terms of system stability, calibration with minimum-ionizing particles and resolution (energy, position and timing) for electrons, and the comparisons of these quantities with GEANT4-based simulation.

Measurements of the proton structure function $F_2$ for $0.6 < Q^2 < 17 {GeV}^2$ and $1.2 \times 10^{-5} < x <1.9 \times 10^{-3}$ from ZEUS 1995 shifted vertex data are presented. From ZEUS $F_2$ data the slopes $dF_2/d\ln Q^2$ at fixed $x$ and $d\ln F_2/d\ln(1/x)$ for $x < 0.01$ at fixed $Q^2$ are derived. For the latter E665 data are also used. The transition region in $Q^2$ is explored using the simplest non-perturbative models and NLO QCD. The data at very low $Q^2$ $\leq 0.65 {GeV}^2$ are described successfully by a combination of generalised vector meson dominance and Regge theory. From a NLO QCD fit to ZEUS data the gluon density in the proton is extracted in the range $3\times 10^{-5} < x < 0.7$. Data from NMC and BCDMS constrain the fit at large $x$. Assuming the NLO QCD description to be valid down to $Q^2\sim 1 {GeV}^2$, it is found that the $q\bar{q}$ sea distribution is still rising at small $x$ and the lowest $Q^2$ values whereas the gluon distribution is strongly suppressed.

We have studied the color-suppressed hadronic decays of neutral B mesons into the final states ${D}^{(*)0}{\ensuremath{\pi}}^{0}$. Using $9.67\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected with the CLEO detector, we observe the decays ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{0}$ and ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{*0}{\ensuremath{\pi}}^{0}$ with the branching fractions $B({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{0})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({2.74}_{\ensuremath{-}0.32}^{+0.36}\ifmmode\pm\else\textpm\fi{}0.55)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $B({\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{*0}{\ensuremath{\pi}}^{0})\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}({2.20}_{\ensuremath{-}0.52}^{+0.59}\ifmmode\pm\else\textpm\fi{}0.79)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. The first error is statistical and the second systematic. The statistical significance of the ${D}^{0}{\ensuremath{\pi}}^{0}$ signal is $12.1\ensuremath{\sigma}$ ( $5.9\ensuremath{\sigma}$ for ${D}^{*0}{\ensuremath{\pi}}^{0}$). Utilizing the ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{(*)0}{\ensuremath{\pi}}^{0}$ branching fractions we determine the strong phases ${\ensuremath{\delta}}_{I,D(*)}$ between isospin $1/2$ and $3/2$ amplitudes in the $D\ensuremath{\pi}$ and ${D}^{*}\ensuremath{\pi}$ final states to be $\mathrm{cos}{\ensuremath{\delta}}_{I,D}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.89\ifmmode\pm\else\textpm\fi{}0.08$ and $\mathrm{cos}{\ensuremath{\delta}}_{I,D*}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.89\ifmmode\pm\else\textpm\fi{}0.08$, respectively.

We present a measurement of the composition of B meson inclusive semileptonic decays using 9.4 ${\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ data taken with the CLEO detector at the $\ensuremath{\Upsilon}(4S)$ resonance. In addition to measuring the charged lepton kinematics, the neutrino four-vector is inferred using the hermiticity of the detector. We perform a maximum likelihood fit over the full three-dimensional differential decay distribution for the fractional contributions from the $\stackrel{\ensuremath{\rightarrow}}{B}{X}_{c}\mathcal{l}\ensuremath{\nu}$ processes with ${X}_{c}=D,$ ${D}^{*},$ ${D}^{**},$ and nonresonant ${X}_{c},$ and the process $\stackrel{\ensuremath{\rightarrow}}{B}{X}_{u}\mathcal{l}\ensuremath{\nu}.$ From the fit results we extract the first and second moments of the ${M}_{X}^{2}$ and ${q}^{2}$ distributions with minimum lepton-energy requirements of 1.0 GeV and 1.5 GeV. We find $〈{M}_{X}^{2}\ensuremath{-}{M}_{D}^{2}〉=(0.456\ifmmode\pm\else\textpm\fi{}0.014\ifmmode\pm\else\textpm\fi{}0.045\ifmmode\pm\else\textpm\fi{}0.109){\mathrm{GeV}}^{2}{/c}^{4}$ with a minimum lepton energy of 1.0 GeV and $〈{M}_{X}^{2}\ensuremath{-}{M}_{D}^{2}〉=(0.293\ifmmode\pm\else\textpm\fi{}0.012\ifmmode\pm\else\textpm\fi{}0.033\ifmmode\pm\else\textpm\fi{}0.048){\mathrm{GeV}}^{2}{/c}^{4}$ with minimum lepton energy of 1.5 GeV. The uncertainties are from statistics, detector systematic effects, and model dependence, respectively. As a test of the HQET and OPE calculations, the results for the ${M}_{X}^{2}$ moment as a function of the minimum lepton energy requirement are compared to the predictions.

The response of the CMS barrel calorimeter (electromagnetic plus hadronic) to hadrons, electrons and muons over a wide momentum range from 2 to 350 GeV/c has been measured. To our knowledge, this is the widest range of momenta in which any calorimeter system has been studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. The analysis of the differences in calorimeter response to charged pions, kaons, protons and antiprotons and a detailed discussion of the underlying phenomena are presented. We also show techniques that apply corrections to the signals from the considerably different electromagnetic (EB) and hadronic (HB) barrel calorimeters in reconstructing the energies of hadrons. Above 5 GeV/c, these corrections improve the energy resolution of the combined system where the stochastic term equals 84.7±1.6% and the constant term is 7.4±0.8%. The corrected mean response remains constant within 1.3% rms.

We report a new measurement of the B-meson semileptonic decay momentum spectrum that has been made with a sample of 9.4 fb−1 of e+e− data collected with the CLEO II detector at the Υ(4S) resonance. Electrons from primary semileptonic decays and secondary charm decays were separated by using charge and angular correlations in Υ(4S) events with a high-momentum lepton and an additional electron. We determined the semileptonic branching fraction to be B(→BXe+νe)=(10.91±0.09±0.24)% from the normalization of the electron-energy spectrum. We also measured the moments of the electron-energy spectrum with minimum energies from 0.6 to 1.5 GeV.Received 8 April 2004DOI:https://doi.org/10.1103/PhysRevD.70.032003©2004 American Physical Society

Using 9.0 fb -1 of integrated luminosity in e + e -collisions near the Υ(4S) mass collected with the CLEO II.V detector we report the first observation of the decay D 0 → K 0 S ηπ 0 .We measure the ratio of branching fractions, BR(D 0 →K 0 S ηπ 0 ) BR(D 0 →K 0 S π 0 ) = 0.46 ± 0.07 ± 0.06.We perform a Dalitz analysis of 155 selected D 0 → K 0 S ηπ 0 candidates and find leading contributions from a 0 (980)K 0 S and K * (892)η intermediate states.

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated.

Abstract The barrel section of the novel MIP Timing Detector (MTD) will be constructed as part of the upgrade of the CMS experiment to provide a time resolution for single charged tracks in the range of 30–60 ps using LYSO:Ce crystal arrays read out with Silicon Photomultipliers (SiPMs). A major challenge for the operation of such a detector is the extremely high radiation level, of about 2 × 10 14 1 MeV(Si) Eqv. n/cm 2 , that will be integrated over a decade of operation of the High Luminosity Large Hadron Collider (HL-LHC). Silicon Photomultipliers exposed to this level of radiation have shown a strong increase in dark count rate and radiation damage effects that also impact their gain and photon detection efficiency. For this reason during operations the whole detector is cooled down to about -35°C. In this paper we illustrate an innovative and cost-effective solution to mitigate the impact of radiation damage on the timing performance of the detector, by integrating small thermo-electric coolers (TECs) on the back of the SiPM package. This additional feature, fully integrated as part of the SiPM array, enables a further decrease in operating temperature down to about -45°C. This leads to a reduction by a factor of about two in the dark count rate without requiring additional power budget, since the power required by the TEC is almost entirely offset by a decrease in the power required for the SiPM operation due to leakage current. In addition, the operation of the TECs with reversed polarity during technical stops of the accelerator can raise the temperature of the SiPMs up to 60°C (about 50°C higher than the rest of the detector), thus accelerating the annealing of radiation damage effects and partly recovering the SiPM performance.

We have searched for CP-violating asymmetries in neutral charm meson decays in 13.7 fb−1 of e+e− collision data at √s≈10.6GeV with the CLEO detector. The measured asymmetries in the rate of D0 and ¯D0 decays to K0Sπ0, π0π0 and K0SK0S final states are (+0.1±1.3)%, (+0.1±4.8)% and (−23±19)%, respectively.Received 19 December 2000DOI:https://doi.org/10.1103/PhysRevD.63.071101©2001 American Physical Society

two typographical errors in Table I of our Letter: In the ninth row of Table I for the K 2 1430, the phase should read 335 not 155.In the eleventh row of Table I for the nonresonant, the phase should read 340 not 160.

We search and find no evidence for CP violation in tau decays into the K(pi)nu(tau) final state. We provide limits on the imaginary part of the coupling constant Lambda describing a relative contribution of the CP violating processes with respect to the standard model to be -0.172<Im(Lambda)<0.067 at 90% C.L.

Using data collected by the CLEO detector in the Upsilon(4S) region, we report new measurements of the exclusive decays of B mesons into final states of the type Lambda_c^+ p-bar n(pi), where n=0,1,2,3. We find signals in modes with one, two and three pions and an upper limit for the two body decay Lambda_c^+ pbar. We also make the first measurements of exclusive decays of B mesons to Sigma_c p-bar n(pi), where n=0,1,2. We find signals in modes with one and two pions and an upper limit for the two body decay Sigma_c p-bar. Measurements of these modes shed light on the mechanisms involved in B decays to baryons.

Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay lambda(+)(c)lambda--> e(+)nu(e). By performing a four-dimensional maximum likelihood fit, we determine the form factor ratio, R= f(2)/f(1) = -0.31 +/- 0.05(stat) +/- 0.04(syst), the pole mass, M(pole) = [2.21 +/- 0.08(stat) +/- 0.14(syst)] GeV/c(2), and the decay asymmetry parameter of the lambda(+)(c), alpha (lambda(c)) = -0.86 +/-0.03(stat) +/- 0.02(syst), for q(2) = 0.67 (GeV/c(2))(2). We compare the angular distributions of the lambda(+)(c) and lambda(-)(c) and find no evidence for CP violation: A(lambda(c)) = (alpha(lambda(c)) + alpha (lambda(c)))/(alpha(lambda(c))-alpha(lambda(c))) = 0.00 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02, where the third error is from the uncertainty in the world average of the CP-violating parameter, A(lambda), for ppi(-).

In e+e− collisions recorded using the CLEO II.V detector we have studied the Cabibbo suppressed decay of D0→π+π−π0 with the initial flavor of the D0 tagged by the decay D*+→D0π+. We use the Dalitz-plot analysis technique to measure the resonant substructure in this final state and observe ρπ and nonresonant contributions by fitting for their amplitudes and relative phases. We describe the ππ S wave with a K-matrix formalism and limit this contribution to the rate to be <2.5%@95% confidence level, in contrast to the large rate observed in D+→π+π−π+ decay. Using the amplitudes and phases from this analysis, we calculate an integrated CP asymmetry of 0.01+0.09−0.07±0.05.Received 29 March 2005Corrected 6 June 2007DOI:https://doi.org/10.1103/PhysRevD.72.031102©2005 American Physical Society

We use data collected by the CLEO III detector at CESR on the Upsilon(5S) resonance to measure the inclusive yield of Ds mesons. Comparing with data taken on the Upsilon(4S), which decays into lighter B mesons, we make a model dependent estimate of the ratio of Bs(*)anti-Bs(*) to the total b anti-b quark pair production at the Upsilon(5S) energy of (16.0+/-2.6+/-5.8)%.

Using the CLEO II.V detector observing ${e}^{+}{e}^{\ensuremath{-}}$ collisions at around 10.6 GeV we search for neutral $D$ mixing in semileptonic ${D}^{0}$ decays tagged in charged ${D}^{*}$ decays. Combining the results from the $Ke\ensuremath{\nu}$ and ${K}^{*}e\ensuremath{\nu}$ channels we find that the rate for $D$ mixing is less than 0.0078 at $90%$ C.L.

Using data taken with the CLEO III detector at the Cornell Electron Storage Ring, we have investigated the direct photon spectrum in the decays $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}gg$, $\ensuremath{\Upsilon}(2\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}gg$, $\ensuremath{\Upsilon}(3\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}gg$. The latter two of these are first measurements. Our analysis procedures differ from previous ones in the following ways: (a) background estimates (primarily from ${\ensuremath{\pi}}^{0}$ decays) are based on isospin symmetry rather than a determination of the ${\ensuremath{\pi}}^{0}$ spectrum, which permits measurement of the $\ensuremath{\Upsilon}(2\mathrm{S})$ and $\ensuremath{\Upsilon}(3\mathrm{S})$ direct photon spectra without explicit corrections for ${\ensuremath{\pi}}^{0}$ backgrounds from, e.g., ${\ensuremath{\chi}}_{bJ}$ states, (b) we estimate the branching fractions with a parametrized functional form (exponential) used for the background, and c) we use the high-statistics sample of $\ensuremath{\Upsilon}(2\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\Upsilon}(1\mathrm{S})$ to obtain a tagged sample of $\ensuremath{\Upsilon}(1\mathrm{S})\ensuremath{\rightarrow}\ensuremath{\gamma}+X$ events, for which there are no QED backgrounds. We determine values for the ratio of the inclusive direct photon decay rate to that of the dominant three-gluon decay $\ensuremath{\Upsilon}\ensuremath{\rightarrow}ggg\text{ }\text{ }({R}_{\ensuremath{\gamma}}=B(gg\ensuremath{\gamma})/B(ggg))$ to be ${R}_{\ensuremath{\gamma}}(1\mathrm{S})=(2.70\ifmmode\pm\else\textpm\fi{}0.01\ifmmode\pm\else\textpm\fi{}0.13\ifmmode\pm\else\textpm\fi{}0.24)%$, ${R}_{\ensuremath{\gamma}}(2\mathrm{S})=(3.18\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.22\ifmmode\pm\else\textpm\fi{}0.41)%$, and ${R}_{\ensuremath{\gamma}}(3\mathrm{S})=(2.72\ifmmode\pm\else\textpm\fi{}0.06\ifmmode\pm\else\textpm\fi{}0.32\ifmmode\pm\else\textpm\fi{}0.37)%$, where the errors shown are statistical, systematic, and theoretical model dependent, respectively. Given a value of ${Q}^{2}$, one can estimate a value for the strong coupling constant ${\ensuremath{\alpha}}_{s}({Q}^{2})$ from ${R}_{\ensuremath{\gamma}}$.

Using 13.7fb−1 of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Ξc0′π+ with the subsequent decay Ξc0′→Ξc0γ, and its isospin partner decaying into Ξc+′π− followed by Ξc+′→Ξc+γ. We measure the following mass differences for the two states: M(Ξc0γπ+)−M(Ξc0)=318.2±1.3±2.9MeV and M(Ξc+γπ−)−M(Ξc+)=324.0±1.3±3.0MeV. We interpret these new states as the JP=12− Ξc1 particles, the charmed-strange analogs of the Λc1+(2593).Received 7 December 2000DOI:https://doi.org/10.1103/PhysRevLett.86.4243©2001 American Physical Society

We report on a search for charmless hadronic B decays to the three-body final states K(0)(S)h(+)pi(-), K(+)h(-)pi(0), K(0)(S)h(+)pi(0) (h(+/-) denotes a charged pion or kaon), and their charge conjugates, using 13.5 fb(-1) of integrated luminosity produced near sqrt[s]=10.6 GeV, and collected with the CLEO detector. We observe the decay B-->K0pi(+)pi(-) with a branching fraction (50(+10)(-9)(stat.)+/-7(syst.))x10(-6) and the decay B-->K(*+)(892)pi(-) with a branching fraction (16(+6)(-5)(stat.)+/-2(syst.))x10(-6).

We have searched a sample of 9.6 million $B\overline{B}$ events for the lepton-flavor-violating decays $\stackrel{\ensuremath{\rightarrow}}{B}{\mathrm{he}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\mu}}^{\ensuremath{\mp}},$ ${B}^{+}\ensuremath{\rightarrow}{h}^{\ensuremath{-}}{e}^{+}{e}^{+},$ ${B}^{+}\ensuremath{\rightarrow}{h}^{\ensuremath{-}}{e}^{+}{\ensuremath{\mu}}^{+},$ and ${B}^{+}\ensuremath{\rightarrow}{h}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{+},$ where h is $\ensuremath{\pi},$ K, $\ensuremath{\rho},$ and ${K}^{*}(892),$ a total of sixteen modes. We find no evidence for these decays, and place 90% confidence level upper limits on their branching fractions that range from 1.0 to $8.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}.$

We present the first study of the vector (Wess-Zumino) current in τ−→K−π−K+ντ decay using data collected with the CLEO III detector at the Cornell Electron Storage Ring. We determine the quantitative contributions to the decay width from the vector and axial vector currents. Within the framework of a model by Kühn and Mirkes, we identify the quantitative contributions to the total decay rate from the intermediate states ωπ, ρ(')π, and K∗K.Received 29 December 2003DOI:https://doi.org/10.1103/PhysRevLett.92.232001©2004 American Physical Society

The decay branching fractions of the three narrow Υ resonances to μ+μ− have been measured by analyzing about 4.3 fb−1 e+e− data collected with the CLEO III detector. The branching fraction B(Υ(1S)→μ+μ−)=(2.49±0.02±0.07)% is consistent with the current world average, but B(Υ(2S)→μ+μ−)=(2.03±0.03±0.08)% and B(Υ(3S)→μ+μ−)=(2.39±0.07±0.10)% are significantly larger than prior results. These new muonic branching fractions imply a narrower total decay width for the Υ(2S) and Υ(3S) resonances and lower other branching fractions that rely on these decays in their determination.Received 3 September 2004DOI:https://doi.org/10.1103/PhysRevLett.94.012001©2005 American Physical Society

Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the Bs meson in e+e- annihilation at the Y(5S) resonance. We find 14 candidates consistent with Bs decays into final states with a J/psi or a Ds(*)- . The probability that we have observed a background fluctuation is less than 8 x 10(-10) . We have established that at the energy of the Y(5S) resonance Bs production proceeds predominantly through the creation of Bs*Bs* pairs. We find sigma(e+e- --> Bs*Bs*) = [0.11(-0.03))(+0.04)(stat) +/- 0.02(syst)]nb , and set the following limits: sigma(e+e- --> BsBs)/ sigma(e+ e- --> Bs*Bs*) <0.16 and [sigma(e+e- --> BsBs*) + sigma(e+e- --> Bs*Bs)]/sigma(e+e- -->Bs*Bs*) < 0.16 (90% C.L.). The mass of the Bs* meson is measured to be M(Bs*) = [5.414+/- 0.001(stat) +/- 0.003(syst)] GeV/c2 .

Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.

Events containing an isolated prompt photon with high transverse energy, together with a balancing jet, have been observed for the first time in photoproduction at HERA. The data were taken with the ZEUS detector, in a γp centre of mass energy range 120–250 GeV. The fraction of the incoming photon energy participating in the production of the prompt photon and the jet, xγ, shows a strong peak near unity, consistent with LO QCD Monte Carlo predictions. In the transverse energy and pseudorapidity range 5 ≤ ETγ < 10 GeV, −0.7 ≤ ηγ < 0.8, ETjet ≥ 5 GeV, and −1.5 ≤ ηjet ≤ 1.8, with xγOBS > 0.8, the measured cross section is 15.3 ± 3.8 ± 1.8 pb, in good agreement with a recent NLO calculation.

The ZEUS detector at HERA has been supplemented with a presampler detector in front of the forward and rear calorimeters. It consists of a segmented scintillator array read out with wavelength-shifting fibers. We discuss its design, construction and performance. Test beam data obtained with a prototype presampler and the ZEUS prototype calorimeter demonstrate the main function of this detector, i.e. the correction for the energy lost by an electron interacting in inactive material in front of the calorimeter.

We have searched for the two-body decay of the B meson to a light pseudoscalar meson h = pi(+/-),K+/-,K(0)(S) and a massless neutral feebly interacting particle X(0) such as the familon, the Nambu-Goldstone boson associated with a spontaneously broken global family symmetry. We find no significant signal by analyzing a data sample containing 9.7x10(6) BBbar mesons collected with the CLEO detector at the Cornell Electron Storage Ring, and set 90% C.L. upper limits italicB(B(+/-) --> h(+/-)X(0)) = 4.9x10(-5) and italicB(B(0) --> K(0)(S)X(0)) = 5.3x10(-5). These limits correspond to a lower bound of approximately 10(8) GeV on the family symmetry breaking scale with vector coupling involving the third generation of quarks.

Using 12.7 fb(-1) of data collected with the CLEO detector at CESR, we observed two-photon production of the cc states chi(c0) and chi(c2) in their decay to pi(+)pi(-)pi(+)pi(-). We measured gamma(gammagamma)(chi(c))xB(chi(c)-->pi(+)pi(-)pi(+)pi(-)) to be 75+/-13(stat)+/-8(syst) eV for the chi(c0) and 6.4+/-1.8(stat)+/-0.8(syst) eV for the chi(c2), implying gamma(gammagamma)(chi(c0)) = 3.76+/-0.65(stat)+/-0.41(syst)+/-1.69(br) keV and gamma(gammagamma)(chi(c2)) = 0.53+/-0.15(stat)+/-0.06(syst)+/-0.22(br) keV. Also, cancellation of dominant experimental and theoretical uncertainties permits a precise comparison of gamma(gammagamma)(chi(c0))/gamma(gammagamma)(chi(c2)), evaluated to be 7.4+/-2.4(stat)+/-0.5(syst)+/-0.9(br), with QCD-based predictions.

Using 9.1 fb-1 of e+ e- data collected at the Upsilon(4S) with the CLEO detector using the Cornell Electron Storage Ring, measurements are reported for both the branching fractions and the helicity amplitudes for the decays B- -> D*0 rho- and B0bar -> D*+ rho-. The fraction of longitudinal polarization in B0bar -> D*+ rho- is found to be consistent with that in B0bar -> D*+ l- nubar at q^2 = M^2_rho, indicating that the factorization approximation works well. The longitudinal polarization in the B- mode is similar. The measurements also show evidence of non-trivial final-state interaction phases for the helicity amplitudes.

The rare $\ensuremath{\tau}$ lepton decays to four explicitly identified hadrons have been studied with the CLEO detector at the Cornell Electron Storage Ring using $(7.56\ifmmode\pm\else\textpm\fi{}0.15)\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected near $\sqrt{s}=10.58\text{ }\text{ }\mathrm{GeV}$. The first statistically significant measurements of $\mathcal{B}({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}},\mathrm{\text{excluding}}{K}^{0})=(7.4\ifmmode\pm\else\textpm\fi{}0.8\ifmmode\pm\else\textpm\fi{}1.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $\mathcal{B}({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}})=(5.5\ifmmode\pm\else\textpm\fi{}1.4\ifmmode\pm\else\textpm\fi{}1.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ are presented, including the first observation of the decay ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}\ensuremath{\omega}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ with branching fraction, $(4.1\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. We publish the first upper limit for $\mathcal{B}({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}})&lt;4.8(6.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ at 90% (95%) confidence level. We measure for the first time the invariant mass distributions, which together with the branching fraction measurements are important ingredients that can be used to extract the standard model parameters, the strange quark mass, and the Cabibbo-Kobayashi-Maskawa element ${V}_{us}$.

Using 13.8 fb(-1) of data collected at or just below the Upsilon(4S) with the CLEO detector, we report the result of a search for the flavor changing neutral current process D0-->gammagamma. We observe no significant signal for this decay mode and determine 90% confidence level upper limits on the branching fractions B(D0-->gammagamma)/B(D0-->pi(0)pi(0))<0.033 and B(D0-->gammagamma)<2.9 x 10(-5).

We report on a search for the recently reported X(3872) state using 15.1 fb(-1) of e(+)e(-) data taken in the sqrt[s] = 9.46-11.30 GeV region. Separate searches for the production of the X(3872) in untagged gammagamma fusion and e(+)e(-) annihilation following initial state radiation are made by taking advantage of the unique angular correlation between the leptons from the decay J/psi --> l(+)l(-) in X(3872) decay to pi(+)pi(-)J/psi. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)Gamma(gammagamma)(X(3872))B(X --> pi(+)pi(-)J/psi) < 12.9 eV and Gamma(ee)(X(3872))B(X- -> pi(+)pi(-)J/psi) < 8.3 eV.

Dijet cross sections are presented using photoproduction data obtained with the ZEUS detector during 1994. These measurements represent an extension of previous results, as the higher statistics allow cross sections to be measured at higher jet transverse energy (E τ jet ). Jets are identified in the hadronic final state using three different algorithms, and the cross sections compared to complete next-to-leading order QCD calculations. Agreement with these calculations is seen for the pseudorapidity dependence of the direct photon events with E T jet > 6 GeV and of the resolved photon events with E t jet > 11 GeV. Calculated cross sections for resolved photon processes with 6 GeV < E T jet < 11 GeV lie below the data.

The cross section for the photoproduction of events containing three jets with a three-jet invariant mass of M_3J > 50 GeV has been measured with the ZEUS detector at HERA. The three-jet angular distributions are inconsistent with a uniform population of the available phase space but are well described by parton shower models and O(alpha alpha_s^2) pQCD calculations. Comparisons with the parton shower model indicate a strong contribution from initial state radiation as well as a sensitivity to the effects of colour coherence.

We present new measurements of branching fractions for the color-favored decays B^- --> D^0 pi^- and Bbar^0 --> D^+ pi^-. Using 9.67 x 10^6 BBbar pairs collected with the CLEO detector, we obtain the branching fractions BR(B^- --> D^0 pi^- =3D (49.7 +/- 1.2 +/- 2.9 +/- 2.2) x 10^{-4} and BR(Bbar^0 --> D^+ pi^- =3D (26.8 +/- 1.2 +/- 2.4 +/- 1.2) x 10^{-4}. The first error is statistical, the second is systematic, and the third is due to the experimental uncertainty on the production ratio of charged and neutral B mesons in Upsilon(4S) decays. These results, together with the current world average for the color-suppressed branching fraction BR(Bbar^0 --> D^0 pi^0), are used to determine the cosine of the strong phase difference delta_I between the I=1/2 and I=3/2 isospin amplitudes. We find cos(delta_I) = 0.863 (+0.024 -0.023) (+0.036 -0.035) (+0.038 -0.030), and obtain a 90% confidence interval of 16.5 degrees < delta_I < 38.1 degrees. This non-zero value of \delta_I strongly suggests the presence of final state interactions in the Dpi system.

The ratio of charged and neutral B meson production at the Upsilon(4S), f_{+-}/f_{00}, is measured through the decays B bar -> D* l- nu_l bar, reconstructed using a partial reconstruction method where the D* is detected only through a pion daughter from the decay D* -> D pi. Using data collected by the CLEO II detector, the charged and neutral B decays are measured in such a way that their ratio is independent of decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This measurement yields the ratio of production fractions times the ratio of semileptonic branching fractions, f_{+-}b_{+}/f_{00}b_0. Assuming that b_+/b_0 is equal to the lifetime ratio tau_+/tau_0 and using the world average value of tau_+/tau_0 as input, we obtain f_{+-}/f_{00}=1.058+- 0.084+- 0.136.

Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the Omega_c (css ground state) in the decay Omega_c -> Omega- e+ nu. We find a signal of 11.4 +- 3.8 (stat) events. The probability that we have observed a background fluctuation is 7.6 x 10-5. We measure BF(Omega_c -> Omega- e+ nu) x sigma(e+ e- -> Omega_c X) = (42.2 +- 14.1 (stat) +- 5.7 (syst)) fb and R = Gamma(Omega_c -> Omega- pi+)/Gamma(Omega_c -> Omega- e+ nu) = 0.41 +- 0.19 (stat) +- 0.04 (syst). This is the first statistically significant observation of an individual decay mode of the Omega_c in e+ e- annhiliation, and the first example of a baryon decaying via beta-emmision, where no quarks from the first generation participate in the reaction.

The CLEO Collaboration has made the first observations of hadronic transitions among bottomonium (bbmacr;) states other than the dipion transitions among Upsilon(nS) states. In our study of Upsilon(3S) decays, we find a significant signal for Upsilon(3S)-->gammaomegaUpsilon(1S) that is consistent with radiative decays Upsilon(3S)-->gammachi(b1,2)(2P), followed by chi(b1,2)(2P)-->omegaUpsilon(1S). The branching ratios we obtain are B[chi(b1)(2P)-->omegaUpsilon(1S)]=(1.63(+0.35+0.16)(-0.31-0.15))% and B[chi(b2)(2P)-->omegaUpsilon(1S)]=(1.10(+0.32+0.11)(-0.28-0.10))%, in which the first error is statistical and the second is systematic.

We analyze $13.8\text{ }\text{ }\mathrm{f}{\mathrm{b}}^{\ensuremath{-}1}$ of the integrated ${e}^{+}{e}^{\ensuremath{-}}$ luminosity collected at 10.6 GeV center-of-mass energy with the CLEO II and CLEO II.V detectors to study exclusive two-photon production of hadrons with masses below $1.7\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$ decaying into the ${K}_{S}^{0}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ final state. We observe two statistically significant enhancements in the $\ensuremath{\eta}(1475)$ mass region. These enhancements have large transverse momentum which rules them out as being due to pseudoscalar resonances but is consistent with the production of axial-vector mesons. We use tagged two-photon events to study the properties of the observed enhancements and associate them with the production of ${f}_{1}(1285)$ and ${f}_{1}(1420)$. Our nonobservation of $\ensuremath{\eta}(1475)$ is inconsistent by more than 2 standard deviations with the first observation of this resonance in two-photon collisions by the L3 experiment. We present our estimates for 90% confidence level upper limits on the products of two-photon partial widths of light pseudoscalar hadrons and their branching fractions into ${K}_{S}^{0}({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}){K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$.

We have searched for the di-pion transition chi_b(2P) -> pi pi chi_b(1P) in the CLEO III sample of Upsilon(3S) decays in the exclusive decay chain: Upsilon(3S) -> gamma chi_b(2P), chi_b(2P) -> pi pi chi_b(1P), chi_b(1P) -> gamma Upsilon(1S), Upsilon(1S) -> lepton pairs. Our studies include both pi+ pi- and pi0 pi0, each analyzed both in fully reconstructed events and in events with one pion undetected. We show that the null hypothesis is not substantiated. Under reasonable assumptions, we find the partial decay width to be Gamma[chi_b(2P) -> pi pi chi_b(1P)] = (0.83 +/- 0.22 +/- 0.08 +/- 0.19) keV, with the uncertainties being statistical, internal CLEO systematics, and common systematics from outside sources.

Current and future high energy physics particle colliders are capable to provide instantaneous luminosities of 1034 cm-2s-1 and above. The high center of mass energy, the large number of simultaneous collision of beam particles in the experiments and the very high repetition rates of the collision events pose huge challenges. They result in extremely high particle fluxes, causing very high occupancies in the particle physics detectors operating at these machines. To reconstruct the physics events, the detectors have to make as much information as possible available on the final state particles. We discuss how timing information with a precision of around 10 ps and below can aid the reconstruction of the physics events under such challenging conditions. High energy photons play a crucial role in this context. About one third of the particle flux originating from high energy hadron collisions is detected as photons, stemming from the decays of neutral mesons. In addition, many key physics signatures under study are identified by high energy photons in the final state. They pose a particular challenge in that they can only be detected once they convert in the detector material. The particular challenge in measuring the time of arrival of a high energy photon lies in the stochastic component of the distance to the initial conversion and the size of the electromagnetic shower. They extend spatially over distances which propagation times of the initial photon and the subsequent electromagnetic shower which are large compared to the desired precision. We present studies and measurements from test beams and a cosmic muon test stand for calorimeter based timing measurements to explore the ultimate timing precision achievable for high energy photons of 10 GeV and above. We put particular focus on techniques to measure the timing with a precision of about 10 ps in association with the energy of the photon. For calorimeters utilizing scintillating materials and light guiding components, the propagation speed of the scintillation light in the calorimeter is important. We present studies and measurements of the propagation speed on a range of detector geometries. Finally, possible applications of precision timing in future high energy physics experiments are discussed.

The performance of electromagnetic calorimeter modules made of proton-irradiated PbWO4 crystals has been studied in beam tests. The modules, similar to those used in the Endcaps of the CMS electromagnetic calorimeter (ECAL), were formed from 5×5 matrices of PbWO4 crystals, which had previously been exposed to 24 GeV protons up to integrated fluences between 2.1× 1013 and 1.3× 1014 cm−2. These correspond to the predicted charged-hadron fluences in the ECAL Endcaps at pseudorapidity η = 2.6 after about 500 fb−1 and 3000 fb−1 respectively, corresponding to the end of the LHC and High Luminosity LHC operation periods. The irradiated crystals have a lower light transmission for wavelengths corresponding to the scintillation light, and a correspondingly reduced light output. A comparison with four crystals irradiated in situ in CMS showed no significant rate dependence of hadron-induced damage. A degradation of the energy resolution and a non-linear response to electron showers are observed in damaged crystals. Direct measurements of the light output from the crystals show the amplitude decreasing and pulse becoming faster as the fluence increases. The latter is interpreted, through comparison with simulation, as a side-effect of the degradation in light transmission. The experimental results obtained can be used to estimate the long term performance of the CMS ECAL.

We measure the primary lepton momentum spectrum in $\overline{B}\ensuremath{\rightarrow}X\mathcal{l}\overline{\ensuremath{\nu}}$ decays, for ${p}_{\mathcal{l}}&gt;~1.5\mathrm{GeV}/c$ in the B rest frame. From this, we calculate various moments of the spectrum. In particular, we find ${R}_{0}\ensuremath{\equiv}{\ensuremath{\int}}_{1.7\mathrm{GeV}}(d\ensuremath{\Gamma}{/dE}_{\mathrm{sl}}{)dE}_{\mathcal{l}}/{\ensuremath{\int}}_{1.5\mathrm{GeV}}(d\ensuremath{\Gamma}{/dE}_{\mathrm{sl}}{)dE}_{\mathcal{l}}=0.6187\ifmmode\pm\else\textpm\fi{}{0.0014}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.0016}_{\mathrm{sys}}$ and ${R}_{1}\ensuremath{\equiv}{\ensuremath{\int}}_{1.5\mathrm{GeV}}{E}_{\mathcal{l}}(d\ensuremath{\Gamma}{/dE}_{\mathrm{sl}}{)dE}_{\mathcal{l}}/{\ensuremath{\int}}_{1.5\mathrm{GeV}}(d\ensuremath{\Gamma}{/dE}_{\mathrm{sl}}{)dE}_{\mathcal{l}}=(1.7810\ifmmode\pm\else\textpm\fi{}{0.0007}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.0009}_{\mathrm{sys}})\mathrm{GeV}.$ We use these moments to determine non-perturbative parameters governing the semileptonic width. In particular, we extract the heavy quark expansion parameters $\overline{\ensuremath{\Lambda}}=(0.39\ifmmode\pm\else\textpm\fi{}{0.03}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.06}_{\mathrm{sys}}\ifmmode\pm\else\textpm\fi{}{0.12}_{\mathrm{th}})\mathrm{GeV}$ and ${\ensuremath{\lambda}}_{1}=(\ensuremath{-}0.25\ifmmode\pm\else\textpm\fi{}{0.02}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}{0.05}_{\mathrm{sys}}\ifmmode\pm\else\textpm\fi{}{0.14}_{\mathrm{th}}){\mathrm{GeV}}^{2}.$ The theoretical constraints used are evaluated through order ${1/M}_{B}^{3}$ in the non-perturbative expansion and ${\ensuremath{\beta}}_{0}{\ensuremath{\alpha}}_{s}^{2}$ in the perturbative expansion. We use these parameters to extract $|{V}_{\mathrm{cb}}|$ from the world average of the semileptonic width and find $|{V}_{\mathrm{cb}}|=(40.8\ifmmode\pm\else\textpm\fi{}{0.5}_{{\ensuremath{\Gamma}}_{\mathrm{sl}}}\ifmmode\pm\else\textpm\fi{}{0.4}_{({\ensuremath{\lambda}}_{1},\overline{\ensuremath{\Lambda}}{)}_{\mathrm{exp}}}\ifmmode\pm\else\textpm\fi{}{0.9}_{\mathrm{th}})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}.$ In addition, we extract the short range b-quark mass ${m}_{b}^{1\mathrm{S}}=(4.82\ifmmode\pm\else\textpm\fi{}{0.07}_{\mathrm{exp}}\ifmmode\pm\else\textpm\fi{}{0.11}_{\mathrm{th}})\mathrm{GeV}{/c}^{2}.$ Finally, we discuss the implications of our measurements for the theoretical understanding of inclusive semileptonic processes.

Using data recorded by the CLEO III detector at the Cornell electron storage ring (CESR), we have made measurements of some properties of the Σc*++ and Σc*0 charmed baryons. In particular: Γ(Σc*++)=14.4−1.5+1.6±1.4 MeV, M(Σc*++)−M(Λc+)=231.5±0.4±0.3 MeV, Γ(Σc*0)=16.6−1.7+1.9±1.4 MeV,M(Σc*0)−M(Λc+)=231.4±0.5±0.3 MeV.Received 27 October 2004DOI:https://doi.org/10.1103/PhysRevD.71.051101©2005 American Physical Society

Inclusive photoproduction of D*+- in ep collisions at HERA has been measured with the ZEUS detector for photon-proton centre of mass energies in the range 115 < W < 280 GeV and photon virtuality Q**2 < 4 GeV**2. The cross section sigma(ep --> D*X) integrated over the kinematic region pt(D*) > 3 GeV and -1.5 < eta(D*) < 1.0 is (10.6+-1.7(stat.)+1.6(syst.)-1.3(syst.)) nb. Differential cross sections as functions of pt(D*), eta(D*) and W are given. The data are compared with two next-to-leading order perturbative QCD predictions. For a calculation using a massive charm scheme the predicted cross sections are smaller than the measured ones. A recent calculation using a massless charm scheme is in agreement with the data.

The dependence of the photon structure on the photon virtuality, Q2, is studied by measuring the reaction e+p→e++jet+jet+X at photon-proton centre-of-mass energies 134<W<223 GeV. Events have been selected in the Q2 ranges ≈ 0 GeV2, 0.1–0.55 GeV2, and 1.5–4.5 GeV2, having two jets with transverse energy ETjet>5.5 GeV in the final state. The dijet cross section has been measured as a function of the fractional momentum of the photon participating in the hard process, xγOBS. The ratio of the dijet cross section with xγOBS<0.75 to that with xγOBS>0.75 decreases as Q2 increases. The data are compared with the predictions of NLO pQCD and leading-order Monte Carlo programs using various parton distribution functions of the photon. The measurements can be interpreted in terms of a resolved photon component that falls with Q2 but remains present at values of Q2 up to 4.5 GeV2. However, none of the models considered gives a good description of the data.

We have searched a sample of $9.6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events for the flavor-changing neutral current decays $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ and $B\ensuremath{\rightarrow}{K}^{*}(892){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$. We subject the latter decay to the requirement that the dilepton mass ${m}_{\ensuremath{\ell}\ensuremath{\ell}}$ exceed 0.5 GeV. There is no indication of a signal. We obtain the $90%$ confidence level upper limits $B(B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}})&lt;1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $B(B\ensuremath{\rightarrow}{K}^{*}(892){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}{)}_{{m}_{\ensuremath{\ell}\ensuremath{\ell}}&gt;0.5\mathrm{GeV}}&lt;3.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. We also obtain an upper limit on the weighted average $0.65B(B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}})+0.35B(B\ensuremath{\rightarrow}{K}^{*}(892){\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}{)}_{{m}_{\ensuremath{\ell}\ensuremath{\ell}}&gt;0.5\mathrm{GeV}}&lt;1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. The weighted-average limit is only $50%$ above the standard model prediction.

Using the combined CLEO II and CLEO II.V data sets of 9.1 fb(-1) at the Upsilon(4S), we measure properties of psi mesons produced directly from decays of the B meson, where "B" denotes an admixture of B+, B-, B0, and B;(0), and "psi" denotes either J/psi(1S) or psi(2S). We report first measurements of psi polarization in B-->psi(direct)X: alpha(psi(1S))=-0.30(+0.07)(-0.06)+/-0.04 and alpha(psi(2S))=-0.45(+0.22)(-0.19)+/-0.04. We also report improved measurements of the momentum distributions of psi produced directly from B decays, correcting for measurement smearing. Finally, we report measurements of the inclusive branching fraction for B-->psiX and B-->chi(c1)X.

We have studied two-body charmless decays of the B meson into the final states ρ0ρ0, K*0ρ0, K*0K*0, K*0¯K*0, K*+ρ0, K*+¯K*0, and K*+K*− using only decay modes with charged daughter particles. Using 9.7×106 B¯B pairs collected with the CLEO detector, we place 90% confidence level upper limits on the branching fractions (1.4–14.1)×10−5, depending on final state and polarization.Received 4 January 2001DOI:https://doi.org/10.1103/PhysRevLett.88.021802©2001 American Physical Society

Using the CLEO II detector at CESR, we measure the ${\ensuremath{\eta}}^{\ensuremath{'}}$ energy spectra in $\ensuremath{\Upsilon}(1S)$ decays that we compare with models of the ${\ensuremath{\eta}}^{\ensuremath{'}}{g}^{*}g$ form factor. This form factor, especially at large ${\ensuremath{\eta}}^{\ensuremath{'}}$ energies, may provide an explanation of the large rate for $\stackrel{\ensuremath{\rightarrow}}{B}{X}_{s}{\ensuremath{\eta}}^{\ensuremath{'}}.$ Our data do not support a large anomalous coupling at higher ${q}^{2}$ and thus the large ${\ensuremath{\eta}}^{\ensuremath{'}}$ rate remains a mystery, possibly requiring a non-standard-model explanation.

Using data recorded by the CLEO II and CLEO II.V detector configurations at CESR, we report new measurements of the masses of the Σ++c and Σ0c charmed baryons, and the first measurements of their intrinsic widths. We find M(Σ++c)−M(Λ+c)=167.4±0.1±0.2MeV, Γ(Σ++c)=2.3±0.2±0.3MeV, and M(Σ0c)−M(Λ+c)=167.2±0.1±0.2MeV,Γ(Σ0c)=2.5±0.2±0.3MeV, where the uncertainties are statistical and systematic, respectively.Received 29 October 2001DOI:https://doi.org/10.1103/PhysRevD.65.071101©2002 American Physical Society

Based on a measurement of high momentum eta' production in B decays, we determine the charmless inclusive B -> eta'X_(nc) branching fraction in the lab-frame momentum interval 2.0<P_eta'<2.7 GeV/c. Using 9.7x10^6 BBbar pairs collected at the Upsilon(4S) center-of-mass energy with the CLEO II and II.V detector configurations, we find Br(B -> eta'X_(nc)) = (4.6 +- 1.1 +- 0.4 +- 0.5)x 10^(-4) in the 2.0<P_(eta')<2.7 GeV/c momentum range, where the uncertainties are statistical, systematic, and from subtraction of background from B decays to charm, respectively.

The two-photon width of chi_c2 (^3P_2) state of charmonium has been measured using 14.4 fb^-1 of e+e- data taken at sqrt{s} = 9.46-11.30 GeV with the CLEO III detector. The two-photon fusion reaction studied is e+e- -> e+e- gamma gamma, gamma gamma -> chi_c2 -> gamma J/psi -> gamma e+e-(mu+mu-). We measure Gamma_{gamma gamma}(chi_c2)xBR(chi_c2 -> gamma J/psi)xBR(J/psi -> e+e- + mu+mu-) = 13.2+-1.4(stat)+-1.1(syst) eV, and obtain Gamma_{gamma gamma}(chi_c2)=559+-57(stat)+-48(syst)+-36(br) eV. This result is in excellent agreement with the result of two-photon fusion measurement by Belle and is consistent with that of the bar{p}p -> chi_c2 -> gamma gamma measurement, when they are both reevaluated using the recent CLEO result for the radiative decay chi_c2 -> gamma J/psi.

Precision timing detectors for high energy physics experiments with temporal resolutions of a few 10 ps are of pivotal importance to master the challenges posed by the highest energy particle accelerators such as the LHC. Calorimetric timing measurements have been a focus of recent research, enabled by exploiting the temporal coherence of electromagnetic showers. Scintillating crystals with high light yield as well as silicon sensors are viable sensitive materials for sampling calorimeters. Silicon sensors have very high efficiency for charged particles. However, their sensitivity to photons, which comprise a large fraction of the electromagnetic shower, is limited. To enhance the efficiency of detecting photons, materials with higher atomic numbers than silicon are preferable. In this paper we present test beam measurements with a Cadmium-Telluride (CdTe) sensor as the active element of a secondary emission calorimeter with focus on the timing performance of the detector. A Schottky type CdTe sensor with an active area of 1cm2 and a thickness of 1 mm is used in an arrangement with tungsten and lead absorbers. Measurements are performed with electron beams in the energy range from 2 GeV to 200 GeV. A timing resolution of 20 ps is achieved under the best conditions.

A study of the antineutrino-jet mass spectrum in e^+p -&gt; antineutrino+X events at center-of-mass energy 300 GeV has been performed with the ZEUS detector at HERA using an integrated luminosity of 47.7 pb^-1. The mass spectrum is in good agreement with that expected from Standard Model processes over the antineutrino -jet mass range studied. No significant excess attributable to the decay of a narrow resonance is observed. By using both e^+p -&gt; e^+ X and e^+p -&gt; antineutrino X data, mass-dependent limits are set on the s-channel production of scalar and vector resonant states. Couplings to first-generation quarks are considered and limits are presented as a function of the e^+q and antineutrino-q branching ratios. These limits are used to constrain the production of leptoquarks and R-parity violating squarks.

Using a 13.7 fb-1 data sample collected with the CLEO II and II.V detectors, we report new branching fraction measurements for two Cabibbo-suppressed decay modes of the D+ meson: BR(D+ -> pi+ pi0) = (1.31 +/- 0.17 +/- 0.09 +/- 0.09) x 10^(-3)and BR(D+ -> K+ K0bar) = (5.24 +/- 0.43 +/- 0.20 +/- 0.34) x 10^(-3) which are significant improvements over past measurements. The errors reflect statistical and systematical uncertainties as well as the uncertainty in the absolute D+ branching fraction scale. We also set the first 90% confidence level upper limit on the branching fraction of the doubly Cabibbo-suppressed decay mode BR(D+ -> K+ pi0) < 4.2 x 10^(-4).

We present final measurements of thirteen charmless hadronic B decay modes from the CLEO experiment.The decay modes include the ten ππ, Kπ, and KK final states and new limits on dibaryonic final states, pp, p Λ, and Λ Λ, as well as a new determination of the ratio B(B → DK)/B(B → Dπ).The results are based on the full CLEO II and CLEO III data samples totalling 15.3 fb -1 at the Υ(4S), and supercede previously published results.

Scintillator based calorimeter technology is studied with the aim to achieve particle detection with a time resolution on the order of a few 10 ps for photons and electrons at energies of a few GeV and above. We present results from a prototype of a 1.4×1.4×11.4 cm3 sampling calorimeter cell consisting of tungsten absorber plates and Cerium-doped Lutetium Yttrium Orthosilicate (LYSO) crystal scintillator plates. The LYSO plates are read out with wave lengths shifting fibers which are optically coupled to fast photo detectors on both ends of the fibers. The measurements with electrons were performed at the Fermilab Test Beam Facility (FTBF) and the CERN SPS H2 test beam. In addition to the baseline setup plastic scintillation counter and a MCP-PMT were used as trigger and as a reference for a time of flight measurement (TOF). We also present measurements with a fast laser to further characterize the response of the prototype and the photo sensors. All data were recorded using a DRS4 fast sampling digitizer. These measurements are part of an R&D program whose aim is to demonstrate the feasibility of building a large scale electromagnetic calorimeter with a time resolution on the order of 10 ps, to be used in high energy physics experiments.

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.

We have searched a sample of 9.6 x 10(6) BB events for the lepton-flavor-violating leptonic B decays, B(0)-->mu(+/-)tau(-/+) and B(0)-->e(+/-)tau(-/+). The tau lepton was detected through the decay modes tau-->lnunu(-) , where l=e, mu. There is no indication of a signal, and we obtain the 90% confidence level upper limits B(B(0)-->mu(+/-)tau(-/+))<3.8 x 10(-5) and B(B(0)-->e(+/-)tau(-/+))<1.3 x 10(-4).

Studies have been done and continue on the design and construction of a Shashlik detector using Radiation hard quartz capillaries filled with wavelength shifting liquid to collect the scintillation light from LYSO crystals for use as a calorimeter in the Phase II CMS upgrade at CERN. The work presented here focuses on the studies of the capillaries and liquids that would best suit the purpose of the detector. Comparisons are made of various liquids, concentrations, and capillary construction techniques will be discussed.

We present a search for the ``wrong-sign'' decay D0 -> K+ pi- pi+ pi- using 9 fb-1 of e+e- collisions on and just below the Upsilon(4S) resonance. This decay can occur either through a doubly Cabibbo-suppressed process or through mixing to a D0bar followed by a Cabibbo-favored process. Our result for the time-integrated wrong-sign rate relative to the decay D0 -> K- pi+ pi- pi+ is (0.0041 +0.0012-0.0011(stat.) +-0.0004(syst.))x(1.07 +-0.10)(phase space), which has a statistical significance of 3.9 standard deviations.

In e+e- collisions recorded using the CLEO II.V detector we have studied the Cabibbo suppressed decay of D0 -> pi+pi-pi0 with the initial flavor of the D0 tagged by the decay D*+ -> D0pi+. We use the Dalitz-plot analysis technique to measure the resonant substructure in this final state and observe \rho\pi and non-resonant contributions by fitting for their amplitudes and relative phases. We describe the pipi S-wave with a K-matrix formalism and limit this contribution to the rate to be < 2.5% @95% confidence level, in contrast to the large rate observed in D+ -> pi+pi-pi+ decay. Using the amplitudes and phases from this analysis, we calculate an integrated CP asymmetry of 0.01^{+0.09}_{-0.07} +/- 0.05.

The CMS electromagnetic calorimeter (ECAL) is made of 75,848 scintillating lead tungstate crystals arranged in a barrel and two endcaps. The scintillation light is read out by avalanche photodiodes in the barrel and vacuum phototriodes in the endcaps, at which point the scintillation pulse is amplified and sampled at 40 MHz by the on-detector electronics. The fast signal from the crystal scintillation enables energy as well as timing measurements from the data collected in proton-proton collisions with high energy electrons and photons. The single-channel time resolution of ECAL measured at beam tests for high energy showers is better than 100 ps. The timing resolution achieved with the data collected in proton-proton collisions at the LHC is discussed. We present how precision timing is used in current physics measurements and discuss studies of subtle calorimetric effects, such as the timing response of different crystals belonging to the same electromagnetic shower. In addition, we present prospects for the high luminosity phase of the LHC (HL-LHC), where we expect an average of 140 concurrent interactions per bunch crossing (pile-up). We discuss studies on how precision time information could be exploited for pileup mitigation and for the assignment of the collision vertex for photons. In this respect, a detailed understanding of the timing performance and of the limiting factors in time resolution are areas of ongoing studies.

We report on a search for a CP-violating asymmetry in the charmless hadronic decay B -> K*(892)+- pi-+, using 9.12 fb^-1 of integrated luminosity produced at \sqrt{s}=10.58 GeV and collected with the CLEO detector. We find A_{CP}(B -> K*(892)+- pi-+) = 0.26+0.33-0.34(stat.)+0.10-0.08(syst.), giving an allowed interval of [-0.31,0.78] at the 90% confidence level.

Light monitoring will play a crucial role in maintaining the energy resolution of the CMS lead tungstate crystal electromagnetic calorimeter (ECAL) in situ at LHC. Since 2001, a laser based monitoring system has been used in the CMS ECAL beam tests at CERN. While the stability of the laser pulse energy and width, measured in 24 hours, is at a level of 3%, a long term degradation of both the laser pulse energy and the width were observed, as well as a drift of the laser pulse center timing at 2 ns/day. This degradation and drift, caused by the natural aging of the DC Kr lamp, would affect respectively the monitoring precision and the synchronization between the laser pulse and the ECAL ADC clock. This paper presents a design and implementation of a software feedback control which stabilizes the laser pulse energy, width and timing. With the software feedback implemented, a stability of the laser pulse energy and width at 3% level and a pulse timing jitter at 2 ns were observed in laser runs lasted for more than 3 months. The 0.5% energy resolution of the CMS crystal ECAL is maintained after applying the laser monitoring corrections in a beam irradiation test.

Differential dijet cross sections have been measured with the ZEUS detector for photoproduction events in which the hadronic final state containing the jets is separated with respect to the outgoing proton direction by a large rapidity gap. The cross section has been measured as a function of the fraction of the photon (ϰγ OBS) and pomeron (β OBS) momentum participating in the production of the dijet system. The observed ϰγ OBS dependence shows evidence for the presence of a resolved- as well as a direct-photon component. The measured cross section da/dβ OBS increases as β OBS increases indicating that there is a sizeable contribution to dijet production from those events in which a large fraction of the pomeron momentum participates in the hard scattering. These cross sections and the ZEUS measurements of the diffractive structure function can be described by calculations based on parton densities in the pomeron which evolve according to the QCD evolution equations and include a substantial hard momentum component of gluons in the pomeron.