W. S. Lockman
A5088675041- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- Superconducting Materials and Applications
- Computational Physics and Python Applications
- Nuclear physics research studies
- Black Holes and Theoretical Physics
- CCD and CMOS Imaging Sensors
- Astrophysics and Cosmic Phenomena
- Advanced Data Storage Technologies
- Lanthanide and Transition Metal Complexes
- Spacecraft and Cryogenic Technologies
- Nuclear reactor physics and engineering
- Stochastic processes and statistical mechanics
- Particle accelerators and beam dynamics
- Electron and X-Ray Spectroscopy Techniques
- Geophysics and Gravity Measurements
University of California, Santa Cruz
2005-2021
The University of Adelaide
2013-2016
Budker Institute of Nuclear Physics
2015-2016
Siberian Branch of the Russian Academy of Sciences
2015-2016
University of Bergen
2016
Institut National de Physique Nucléaire et de Physique des Particules
2012
Centre National de la Recherche Scientifique
2012
Laboratoire d’Annecy de Physique des Particules
2012
Stanford Synchrotron Radiation Lightsource
1985-2004
Stanford University
2004
We search for single-photon events in 53 fb−1 of e+e− collision data collected with the BABAR detector at PEP-II B-Factory. look a single high-energy photon and large missing momentum energy, consistent production spin-1 particle A′ through process e+e−→γA′; A′→invisible. Such particles, referred to as "dark photons," are motivated by theories applying U(1) gauge symmetry dark matter. find no evidence such processes set 90% confidence level upper limits on coupling strength mass range mA′≤8...
Many models of physics beyond the Standard Model predict existence new Abelian forces with gauge bosons mediating interactions between "dark sectors" and Model. We report a search for dark boson Z' coupling only to second third generations leptons in reaction e+e- -> mu+mu- Z', using 514 fb-1 data collected by BABAR experiment. No significant signal is observed masses range 0.212 - 10 GeV. Limits on parameter g' as low 7x10^-4 are derived, leading improvements bounds compared those...
We report a revised determination of charmed-D-meson absolute branching fractions based on complete reconstruction DD¯ events at the ψ(3770). Two backgrounds, Cabibbo-suppressed and multi-π0 D decays, are addressed in detail. The first measurement decay D0→K−π+π0π0 establishes sensitivity to hitherto unobserved modes. Removal both backgrounds reduces values our previously reported by (21-24)%, leaving their ratios largely unchanged. new unable account fully for deficit charm production...
A new technique is applied to data collected at the $\ensuremath{\psi}(3770)$ resonance derive charmed-$D$-meson branching fractions without relying on measurement of $D$-production cross sections. Measurements are presented for three decay modes ${D}^{0} ({K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}, {D}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}, \mathrm{and} {K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}$ and four...
Measurements of the branching ratios ten Cabibbo-suppressed hadronic weak decays ${D}^{+}$ and ${D}^{0}$ are presented from data collected with Mark III detector SPEAR. In addition to previously observed channels ${D}^{0}$\ensuremath{\rightarrow}${K}^{\mathrm{\ensuremath{-}}}$${K}^{+}$ ${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$${\ensuremath{\pi}}^{+}$, we report new measurements...
Absolute branching fractions for the ${\mathit{D}}_{\mathit{l}3}$ and ${\mathit{D}}_{\mathit{l}4}$ decays ${\mathit{D}}^{+}$\ensuremath{\rightarrow}K\ifmmode\bar\else\textasciimacron\fi{} $^{0}$${\mathit{e}}^{+}$${\ensuremath{\nu}}_{\mathit{e}}$,${\mathit{D}}^{+}$\ensuremath{\rightarrow}K\ifmmode\bar\else\textasciimacron\fi{} $^{0}\mathrm{\ensuremath{\mu}}^{+}$${\ensuremath{\nu}}_{\mathrm{\ensuremath{\mu}}}$, $^{\mathrm{*}0}$${\mathit{e}}^{+}$${\ensuremath{\nu}}_{\mathit{e}}$,...
A dedicated measurement of additional radiation in e+e−→μ+μ−γ and e+e−→π+π−γ initial-state-radiation events is presented using the full BABAR data sample. For first time results are at next-to- next-to-next-to-leading order, with one two photons, respectively, for from initial final states. Comparison predictions phokhara afkqed Monte Carlo generators performed, revealing discrepancies one-photon rates angular distributions former. This disagreement has a negligible effect on e+e−→π+π−(γ)...
We determine the resonant substructure of D→K¯πππ decays, extracting relative fractions and phases amplitudes contributing to K−π+π+π−, K¯0π+π+π−, K−π+π+π0, K¯0π+π−π0 final states. find that two-body decay modes account for at least 75% these decays. obtain branching ratios D→K¯a1(1260), D→K¯*ρ, D→K¯1(1270)π, D→K¯1(1400)π, D0→K¯0ω modes, as well several three- four-body modes. In case D→K¯a1(1260) we all three possible isospin combinations, enabling us extract isospin-½ -32 amplitudes, their...
We present a study of the radiative decay J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\varphi}\ensuremath{\varphi} in \ensuremath{\gamma}${\mathit{K}}^{+}$${\mathit{K}}^{\mathrm{\ensuremath{-}}}$${\mathit{K}}^{+}$${\mathit{K}}^{\mathrm{\ensuremath{-}}}$ and \ensuremath{\gamma}${\mathit{K}}^{+}$${\mathit{K}}^{\mathrm{\ensuremath{-}}}$${\mathit{K}}_{\mathit{S}}^{0}$${\mathit{K}}_{\mathit{L}}^{0}$ final states. A pseudoscalar state is observed...
We present measurements of the branching fraction and time-dependent CP asymmetries in B0->J/Psi pi0 decays based on 466 million Y(4S)->BBbar events collected with BaBar detector at SLAC PEP-II asymmetric-energy B factory. measure asymmetry parameters S=-1.23 +/- 0.21 0.04 C=-0.20 0.19 0.03, where measured value S is 4.0 standard deviations from zero including systematic uncertainties. The determined to be B(B0->J/Psi pi0)=(1.69 0.14 0.07)*10^{-5}.
We study the processes $\gamma \gamma \to K^0_S K^{\pm}\pi^{\mp}$ and K^+ K^- \pi^0$ 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. observe $\eta_c$ decays to both final states perform Dalitz plot analyses model-independent partial wave analysis technique. This allows measurement mass-dependence $I=1/2$ $K \pi$ $\mathcal{S}$-wave amplitude...
We present measurements of the inclusive production antideuterons in $e^+e^-$ annihilation into hadrons at $\approx 10.58 \mathrm{\,Ge\kern -0.1em V}$ center-of-mass energy and $\Upsilon(1S,2S,3S)$ decays. The results are obtained using data collected by BABAR detector PEP-II electron-positron collider. Assuming a fireball spectral shape for emitted antideuteron momentum, we find $\mathcal{B}(\Upsilon(1S) \to \bar{d}X) = (2.81 \pm 0.49 \mathrm{(stat)} {}^{+0.20}_{-0.24} \mathrm{(syst)})/!...
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 weak hadronic decay ${D}^{0}\ensuremath{\rightarrow}{\overline{K}}^{0}{K}^{+}{K}^{\ensuremath{-}}$ is observed in a data sample of 9.3 ${\mathrm{pb}}^{\ensuremath{-}1}$ collected with the Mark III detector at $\ensuremath{\psi}(3770)$ resonance. An analysis ${K}^{+}{K}^{\ensuremath{-}}$ subsystem suggests that while proceeds part through ${\overline{K}}^{0}\ensuremath{\varphi}$ channel, providing evidence for presence nonspectator amplitudes ${D}^{0}$ decays, significant fraction decays...
We report a Dalitz plot analysis of charmless hadronic decays charged $B$ mesons to the final state $K_{\rm S}^{0}\pi^{+}\pi^{0}$ using full BaBar dataset $470.9\pm2.8$ million $B\bar{B}$ events collected at $\Upsilon(4S)$ resonance. measure overall branching fraction and $CP$ asymmetry be ${\cal B}\left(B^{+}\to K^{0}\pi^{+}\pi^{0}\right) = \left(45.9 \pm 2.6 3.0^{+8.6}_{-0.0}\right)\times10^{-6}$ $A_{CP}\left(B^{+}\to 0.07 0.05 0.03^{+0.02}_{-0.03}$, where uncertainties are statistical,...
A search is presented for the decay Υ(1S)→γA0, A0→c¯c, where A0 a candidate CP-odd Higgs boson of next-to-minimal supersymmetric standard model. The based on data collected with BABAR detector at Υ(2S) resonance. sample Υ(1S) mesons selected via Υ(2S)→π+π−Υ(1S). A0→c¯c identified through reconstruction hadronic D0, D+, and D∗(2010)+ meson decays. No significant signal observed. measured 90% confidence-level upper limits product branching fraction B(Υ(1S)→γA0)×B(A0→c¯c) range from 7.4×10−5 to...
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...
The silicon-vertex tracker (SVT) for the BaBar Experiment at PEP-H Asymmetric B Factory Stanford Linear Accelerator Center (SLAC), is a five-layer double-sided ac-coupled silicon-microstrip detector. It crucial element precise measurement of decay position mesons, satisfying severe constraints imposed by accelerator design, in terms geometry interaction region and conditions operation. In following paper, SVT performance described. Radiation issues are discussed results different tests aimed...
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 ($ψ_D$) with branching fractions accessible at factories. We present search for $B \rightarrow Λψ_D$ using data collected by $BABAR$ experiment SLAC. reaction is identified fully reconstructing accompanying requiring single $Λ$ remaining particles. No significant signal observed,...
The Crystal Ball detector at the DESY storage ring DORIS II has been used to study radiative decays of Υ(2S) resonance. We report on analysis exclusive channel Υ(2S)→γχb, χb→γΥ(1S)→e+e− or μ+μ−. detect two χb states by observing monochromatic photon lines energies (107.0±1.1±1.3) MeV and (131.7±0.9±1.3) MeV, respectively. product branching ratios B[Υ(2S)→γχb]×B[χb→γΥ(1S) ] are (1.6±0.3±0.2)% for first state (2.1±0.3±0.3)% second. For ratio third state, which observed in inclusive...