J. G. Smith
A5008637390- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Computational Physics and Python Applications
- Superconducting Materials and Applications
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Cosmology and Gravitation Theories
- Radiation Detection and Scintillator Technologies
- Distributed and Parallel Computing Systems
- Theoretical and Computational Physics
- Nuclear physics research studies
- Advanced Data Storage Technologies
- Black Holes and Theoretical Physics
- Scientific Computing and Data Management
- Physics of Superconductivity and Magnetism
- Molecular spectroscopy and chirality
- Stochastic processes and statistical mechanics
- Advanced NMR Techniques and Applications
University of Colorado Boulder
2004-2014
Laboratoire d’Annecy de Physique des Particules
2005-2006
Colorado State University
2005
Stanford Synchrotron Radiation Lightsource
2004
Stanford University
2004
SLAC National Accelerator Laboratory
2004
Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce light mediator, so-called photon (A′), connecting sector to standard model. We present search for reaction e+e−→γA′, A′→e+e−, μ+μ− using 514 fb−1 data collected with BABAR detector. observe no statistically significant deviations from model predictions, and we set 90% confidence level upper limits on mixing strength between at 10−4−10−3...
A precise measurement of the cross section for process e+e−→K+K−(γ) from threshold to an energy 5 GeV is obtained with initial-state radiation (ISR) method using 232 fb−1 data collected BABAR detector at e+e− center-of-mass energies near 10.6 GeV. The uses effective ISR luminosity determined e+e−→μ+μ−(γ)γISR same set. corresponding lowest-order contribution hadronic vacuum polarization term in muon magnetic anomaly found be aμKK,LO=(22.93±0.18stat±0.22syst)×10−10. charged kaon form factor...
We present a search for the decay $\B^+ \to \ell^+ \nu_{\ell} (\ell = \tau, \mu, \mathrm{or} e)$ in $(458.9 \pm 5.1) \times 10^{6}$ $\Upsilon(4S)$ decays recorded with Babar detector at SLAC PEP-II $B$-Factory. A sample of events one reconstructed exclusive semi-leptonic B ($B^{-}\to D^{0} \ell^{-}\bar{\nu} X$) is selected, and recoil \nu_{\ell}$ signal performed. The $\tau$ identified following channels: $\tau^+ e^+ \nu_e \overline{\nu}_\tau$, \mu^+ \nu_{\mu} \overline{\nu}_{\tau}$, \pi^+...
We study the process $e^+e^- \to \pi^+\pi^-\eta \gamma$, where photon is radiated from initial state. About 8000 fully reconstructed events of this are selected BaBar data sample with an integrated luminosity 469~fb$^{-1}$. Using $\pi^+\pi^-\eta$ invariant mass spectrum we measure \pi^+\pi^-\eta$ cross section in $e^+e^-$ center-of-mass energy range 1.15 to 3.5 GeV. The well described by Vector-Meson Dominance model four $\rho$-like states. observe $49\pm9$ $J/\psi$ decay $\pi^+\pi^-\eta$,...
We study the reaction e+e−→e+e−ηc, ηc→KSK±π∓ and obtain ηc mass width values 2982.2±0.4±1.6 MeV/c2 31.7±1.2±0.8 MeV, respectively. find Γ(ηc→γγ)B(ηc→KK¯π)=0.374±0.009±0.031 keV, measure γγ*→ηc transition form factor in momentum transfer range from 2 to 50 GeV2. The analysis is based on 469 fb−1 of integrated luminosity collected at PEP-II with BABAR detector e+e− center-of-mass energies near 10.6 GeV.19 MoreReceived 16 February 2010DOI:https://doi.org/10.1103/PhysRevD.81.052010©2010 American...
We study the processes γγ→K+K−η and γγ→K+K−π0 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 Υ(nS) (n=2,3,4) resonances. observe ηc→K+K−π0 ηc→K+K−η decays, measure their relative branching fraction, perform Dalitz plot analysis for each decay. K∗0(1430)→Kη decay its fraction to Kπ mode be R(K∗0(1430))=B(K∗0(1430)→Kη)B(K∗0(1430)→Kπ)=0.092±0.025+0.010−0.025. The results correspond first...
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)...
The ratio Rτμ(Υ(1S))=ΓΥ(1S)→τ+τ−/ΓΥ(1S)→μ+μ− is measured using a sample of (121.8±1.2)×106Υ(3S) events recorded by the BABAR detector. This measurement intended as test lepton universality and search for possible light pseudoscalar Higgs boson. In standard model (SM) this expected to be close 1. Any significant deviations would violate could introduced coupling analysis studies decays Υ(3S)→Υ(1S)π+π−, Υ(1S)→l+l−, where l=μ, τ. result, Rτμ(Υ(1S))=1.005±0.013(stat)±0.022(syst), shows no...
We report the measurement of baryonic B decay B- -> SigmaC++ p- pi- pi-. Using a data sample 467*10^6 B-bar pairs collected with BaBar detector at PEP-II storage ring SLAC, measured branching fraction is (2.98 +/- 0.16 (stat) 0.15 (syst) 0.77 (LambdaC+))*10^{-4}, where last error due to uncertainty in LambdaC+ p+ K- pi+. The suggest existence resonant subchannels LambdaC(2595)+ and, possibly, anti-Delta-- see unexplained structures m(SigmaC++ pi-) 3.25 GeV/c^2, 3.8 and 4.2 GeV/c^2.
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...
We study the Upsilon(3S,2S)->eta Upsilon(1S) and Upsilon(3S,2S)->pi+pi- transitions with 122 million Upsilon(3S) 100 Upsilon(2S) mesons collected by BaBar detector at PEP-II asymmetric energy e+e- collider. measure B[Upsilon(2S)->eta Upsilon(1S)]=(2.39+/-0.31(stat.)+/-0.14(syst.))10^-4 Gamma[Upsilon(2S)->eta Upsilon(1S)]/Gamma[Upsilon(2S)-> pi+pi- Upsilon(1S)]=(1.35+/-0.17(stat.)+/-0.08(syst.))10^-3. find no evidence for Upsilon(3S)->eta obtain B[Upsilon(3S)->eta Upsilon(1S)]<1.0 10^-4...
We report a measurement of the ${D}^{0}$ meson mass using decay chain ${D}^{*}(2010{)}^{+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$ with ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}^{\ensuremath{-}}{K}^{+}{\ensuremath{\pi}}^{+}$. The data were recorded BABAR detector at center-of-mass energies and near $\mathit{\ensuremath{\Upsilon}}(4S)$ resonance, correspond to an integrated luminosity approximately $477\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. obtain...
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...
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,...
Using the entire <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi mathvariant="normal">ϒ</a:mi><a:mo stretchy="false">(</a:mo><a:mn>4</a:mn><a:mi>S</a:mi><a:mo stretchy="false">)</a:mo></a:math> dataset, first two-dimensional unbinned angular analysis of semileptonic decay <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mover accent="true"><f:mi>B</f:mi><f:mo stretchy="false">¯</f:mo></f:mover><f:mo...
We present a new technique, ``tau polarimetry,'' for measuring the longitudinal beam polarization in an ${e}^{+}{e}^{\ensuremath{-}}$ collider through analysis of ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ events. By exploiting sensitivity $\ensuremath{\tau}$ decay kinematics to beams, we demonstrate that can be measured with 3 per mil systematic uncertainty at interaction point using technique is independent spin and...