A5012250148- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Computational Physics and Python Applications
- Medical Imaging Techniques and Applications
- Black Holes and Theoretical Physics
- Superconducting Materials and Applications
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Stochastic processes and statistical mechanics
- advanced mathematical theories
- Cosmology and Gravitation Theories
- Radioactive Decay and Measurement Techniques
- Stochastic processes and financial applications
- Electron Spin Resonance Studies
- Material Properties and Failure Mechanisms
- Photonic and Optical Devices
- Sports Dynamics and Biomechanics
- Nuclear reactor physics and engineering
- Quantum chaos and dynamical systems
California Institute of Technology
1999-2022
Laboratoire d’Annecy de Physique des Particules
2001-2002
Institute of High Energy Physics
1996-1998
Boston University
1996
National Taiwan University
1981
A data-driven energy scan in the immediate vicinity of τ pair production threshold has been performed using Beijing Spectrometer at Electron-Positron Collider. Approximately 5 pb−1 data, distributed over 12 points, have collected. previous mass value for lepton, obtained only eμ final state, published. In this paper, BES result on measurement is presented. The analysis based combined data from ee, eμ, eh, μμ, μh, and hh states, where h denotes a charged π or K. maximum likelihood fit to...
We study the processes $\gamma \gamma \to \eta_c \eta' K^+ K^-$, $\eta' \pi^+ \pi^-$, and $\eta \pi^-$ using a data sample of 519 $fb^{-1}$ recorded with BaBar detector operating at SLAC PEP-II asymmetric-energy $e^+e^-$ collider center-of-mass energies near $\Upsilon(nS)$ ($n = 2,3,4$) resonances. This is first observation decay $\eta_c K^-$ we measure branching fraction $\Gamma(\eta_c K^-)/(\Gamma(\eta_c \pi^-)=0.644\pm 0.039_{\rm stat}\pm 0.032_{\rm sys}$. Significant interference...
A dedicated measurement of additional radiation in e+e−→μ+μ−γ and e+e−→π+π−γ initial-state-radiation events is presented using the full BABAR data sample. For first time results are at next-to- next-to-next-to-leading order, with one two photons, respectively, for from initial final states. Comparison predictions phokhara afkqed Monte Carlo generators performed, revealing discrepancies one-photon rates angular distributions former. This disagreement has a negligible effect on e+e−→π+π−(γ)...
Axionlike particles (ALPs) are predicted in many extensions of the standard model, and their masses can naturally be well below electroweak scale. In presence couplings to bosons, these could emitted flavor-changing B meson decays. We report herein a search for an ALP, a, reaction B^{±}→K^{±}a, a→γγ using data collected by BABAR experiment at SLAC. No significant signal is observed, 90% confidence level upper limits on ALP coupling bosons derived as function mass, improving current...
The process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$ is studied at a center-of-mass energy near the $\mathrm{\ensuremath{\Upsilon}}(4S)$ resonance using data sample of $469\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with BABAR detector PEP-II collider. We have performed precise measurement...
Hadronic decays of the P-wave spin-triplet charmonium states χcJ(J=0,1,2) are studied using a sample ψ(2S) collected by BES detector operating at BEPC storage ring. Branching fractions for χc1→K0SK+π−+c.c., χc0→K0SK0S, χc2→K0SK0S, χc0→φφ, χc2→φφ and χcJ→K+K−K+K− measured first time, those χcJ→π+π−π+π−, χcJ→π+π−K+K−, χcJ→π+π−p¯p χcJ→3(π+π−) with improved precision. In addition, we determine masses χc0 ηc to be Mχc0=3414.1±0.6(stat)±0.8(syst)MeV Mηc=2975.8±3.9(stat)±1.2(syst)MeV. Received 15...
The Beijing Spectrometer (BES) experiment has observed purely leptonic decays of the ${D}_{s}$ meson in reaction ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{s}^{+}{D}_{s}^{\ensuremath{-}}$ at a c.m. energy 4.03 GeV. Three events are which one hadronically to $\ensuremath{\varphi}\ensuremath{\pi}$, ${\overline{K}}^{*0}K$, or ${\overline{K}}^{0}K$, and other leptonically $\ensuremath{\mu}{\ensuremath{\nu}}_{\ensuremath{\mu}}$...
This article presents a model-independent search for an additional, mostly sterile, heavy neutral lepton (HNL), that is capable of mixing with the Standard Model $\ensuremath{\tau}$ neutrino strength $|{U}_{\ensuremath{\tau}4}{|}^{2}$, corresponding to absolute square extended Pontecorvo-Maki-Nakagawa-Sakata matrix element. Data from BABAR experiment, total integrated luminosity $424\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, are analyzed using kinematic approach makes no assumptions...
We study the processes ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$, ${K}_{S}^{0}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$, and...
A new mechanism has been proposed to simultaneously explain the presence of dark matter and matter-antimatter asymmetry in universe. This scenario predicts exotic $B$ meson decays into a baryon sector anti-baryon ($\psi_D$) with branching fractions accessible at factories. We present search for $B \rightarrow \Lambda \psi_D$ using data collected by $BABAR$ experiment SLAC. reaction is identified fully reconstructing accompanying requiring single $\Lambda$ remaining particles. No significant...
The processes $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, $\ensuremath{\gamma}{K}^{+}{K}^{\ensuremath{-}}$, and $\ensuremath{\gamma}p\overline{p}$ have been studied using a sample of $3.79\ifmmode\times\else\texttimes\fi{}{10}^{6}\ensuremath{\psi}(2S)$ decays. We determine the total width ${\ensuremath{\chi}}_{c0}$ to be...
The cross section for e+e−→ρπ has been measured by the BES detector at BEPC center-of-mass energies covering a 40 MeV interval spanning Jψ resonance. data are used to search vector gluonium state hypothesized Brodsky, Lepage, and Tuan as an explanation of ρπ puzzle in charmonium physics. shape is compatible with that total hadronic section. No distortions indicating presence glueball seen.Received 19 October 1995DOI:https://doi.org/10.1103/PhysRevD.54.1221©1996 American Physical Society
Using a sample of 3.8 M ψ(2S) events accumulated with the BES detector, process ψ(2S)→π+π−J/ψ is studied. The angular distributions are compared general decay amplitude analysis Cahn. We find that dipion system requires some D wave amplitude, as well S wave. On other hand, J/ψ−(π+π−) relative momentum consistent being pure have been fit to heavy quarkonium models, including Novikov-Shifman model. This model, which written in terms parameter κ, predicts pions should be present. determine...
A comparison of the rates for ψ(2S)→π+π−J/ψ, J/ψ→l+l− and J/ψ→ anything is used to determine J/ψ leptonic branching fractions. The results are B(J/ψ→e+e−)=(5.90±0.05±0.10)% B(J/ψ→μ+μ−)=(5.84±0.06±0.10)%, where first error statistical second systematic. Assuming lepton universality, fraction B(J/ψ→l+l−)=(5.87±0.04±0.09)% per species. This result estimate QCD scale factor ΛMS¯(4) strong coupling constant αs. Received 11 June 1998DOI:https://doi.org/10.1103/PhysRevD.58.092006©1998 American...
Purely leptonic decays of the charged D meson have been studied using reaction e+e−→D∗+D− at a center mass energy 4.03 GeV. A search was performed for D→μνμ recoiling against D0 or D+ which had reconstructed from its hadronic decay products. single event candidate found in e+e−→D∗+D−, where D∗+→π+D0 with D0→K−π+, and D− decaying via D−→μ−ν̄μ. This yields branching fraction value B(D→μνμ)=0.08−0.05−0.02+0.16+0.05%, corresponding pseudoscalar constant fD=300−150−40+180+80 MeV.
The decays of the $\ensuremath{\psi}(2S)$ into vector plus tensor meson final states have been studied for first time using BES detector. We determine upper limits on branching fractions $\ensuremath{\omega}{f}_{2}$, $\ensuremath{\rho}{a}_{2}$, ${K}^{*0}{\overline{K}}_{2}^{*0}+\mathrm{c}.\mathrm{c}.$, and $\ensuremath{\varphi}{f}_{2}^{\ensuremath{'}}(1525)$ that are, in each case, significantly smaller than corresponding $J/\ensuremath{\psi}$ meson, scaled according to expectations perturbative QCD.
A new dark sector antibaryon, denoted ψD, could be produced in decays of B mesons. This Letter presents a search for B+→ψD+p (and the charge conjugate) e+e− annihilations at 10.58 GeV, using data collected BABAR experiment. Data corresponding to an integrated luminosity 398 fb−1 are analyzed. No evidence signal is observed. Branching fraction upper limits range from 10−7–10−5 obtained 90% confidence level masses 1.0<mψD<4.3 GeV/c2. The result also reinterpreted provide first on...
Radiative decays of the radially excited charmonium resonance, \psi(2S), into \pi\pi, K Kbar and \eta\eta final states have been measured in a sample 3.96 * 10^6 \psi(2S) events collected by BES collaboration. The branching ratios B(\psi(2S) -> \gamma f_{2}(1270)) = (2.27 +- 0.26 0.39) 10^{-4} f_0(1710)) B(f_0(1710) K^+ K^-) (5.59 1.12 0.93) 10^{-5} are obtained. When compared to corresponding radiative J/\psi decays, observed decay rates f_2(1270) f_0(1710) consistent with 15% rule.
We report measurements of branching fractions for ψ(2S) decays into ωπ+π−, b1π, ωf2(1270), ωK+K−, ωpp¯, φπ+π−, φf0(980), φK+K−, and an upper limit φpp¯ final states based on a data sample (4.02±0.22)×106ψ(2S) events collected with the BESI detector at Beijing Electron-Positron Collider. The b1π ωf2(1270) update previous BES results, while those other decay modes are first measurements. ratios J/ψ smaller than what is expected from 12% rule by factor 5 2 studied channels consistent...
We present a search for seven lepton-flavor-violating neutral charm meson decays of the type D0→X0e±μ∓, where X0 represents π0, K0S, ¯K*0, ρ0, ϕ, ω, or η meson. The analysis is based on 468 fb−1 e+e− annihilation data collected at close to Υ(4S) resonance with BABAR detector SLAC National Accelerator Laboratory. No significant signals are observed, and we establish 90% confidence level upper limits branching fractions in range (5.0−22.5)×10−7. between 1 2 orders magnitude more stringent than...
A sample of $3.79\ifmmode\times\else\texttimes\fi{}{10}^{6}\ensuremath{\psi}(2S)$ events is used to study the decays charmonium axial-vector plus pseudoscalar mesons. The branching fraction for decay $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}{b}_{1}^{\ifmmode\pm\else\textpm\fi{}}(1235){\ensuremath{\pi}}^{\ensuremath{\mp}}$ agrees with expectations based on scaling corresponding $J/\ensuremath{\psi}$ fraction. Flavor-SU(3)-violating ${K}_{1}(1270)$- ${K}_{1}(1400)$ asymmetries opposite...
We report first measurements of the branching fractions B(ψ2S→γη′)=(1.54±0.31±0.20)×10−4 and B(ψ2S→γη)=(0.53±0.31±0.08)×10−4. The ψ(2S)→γη′ result is consistent with expectations a model that considers possibility η′−ηc(2S) mixing. ratio ψ(2S)→γη rates used to determine pseudoscalar octet-singlet mixing angle.Received 5 February 1998DOI:https://doi.org/10.1103/PhysRevD.58.097101©1998 American Physical Society
In a sample of 7.8 million J/ψ decays collected in the Beijing Spectrometer, process J/ψ→γηc is observed for five different ηc decay channels: K+K−π+π−, π+π−π+π−, K±KS0π∓ (with KS0→π+π−), φφ φ→K+K−) and K+K−π0. From these signals, we determine mass to be 2976.6±2.9±1.3 MeV. Combining this result with previously reported from similar study using ψ(2S)→γηc detected same spectrometer gives mηc=2976.3±2.3±1.2 For combined samples, obtain Γηc=11.0±8.1±4.1 MeV.Received 3 February...