J. A. McKenna
A5034848878- 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 Detector Development and Performance
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Black Holes and Theoretical Physics
- Atomic and Subatomic Physics Research
- Laser-Matter Interactions and Applications
- Superconducting Materials and Applications
- Nuclear physics research studies
- Mass Spectrometry Techniques and Applications
- Cosmology and Gravitation Theories
- Advanced Fiber Laser Technologies
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Radiation Detection and Scintillator Technologies
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Spectroscopy and Quantum Chemical Studies
- Semiconductor materials and devices
- Advanced Data Storage Technologies
University of Pittsburgh
2023
Southwest University
2023
Shanghai University
2023
Shanghai Institute of Organic Chemistry
2023
Indian Institute of Technology Hyderabad
2023
University of British Columbia
2013-2022
Institute of Particle Physics
1985-2020
Novosibirsk State Technical University
2018-2020
Scuola Normale Superiore
2019
Kansas State University
2007-2018
Based on the full BABAR data sample, we report improved measurements of ratios R(D(*))=B(B[over ¯]→D(*)τ(-)ν[over ¯](τ))/B(B[over ¯]→D(*)ℓ(ℓ)(-)ν[over ¯](ℓ)), where ℓ is either e or μ. These are sensitive to new physics contributions in form a charged Higgs boson. We measure R(D)=0.440±0.058±0.042 and R(D(*))=0.332±0.024±0.018, which exceed standard model expectations by 2.0σ 2.7σ, respectively. Taken together, our results disagree with these at 3.4σ level. This excess cannot be explained...
Based on the full BaBar data sample, we report improved measurements of ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B l Nu), where is either e or mu. These are sensitive to new physics contributions in form a charged Higgs boson. We measure R(D) 0.440 +- 0.058 0.042 and R(D*) 0.332 0.024 0.018, which exceed Standard Model expectations by 2.0 sigma 2.7 sigma, respectively. Taken together, our results disagree with these at 3.4 level. This excess cannot be explained boson type II two-Higgs-doublet...
We study initial-state radiation events, ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\gamma}}_{\mathrm{ISR}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$, with data collected the BABAR detector. observe an accumulation of events near $4.26\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ in invariant-mass spectrum ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$. Fits to mass indicate that a broad resonance about is...
We have observed a narrow state near 2.32 GeV/c2 in the inclusive D+sπ0 invariant mass distribution from e+e− annihilation data at energies 10.6 GeV. The width is consistent with experimental resolution. small intrinsic and quantum numbers of final indicate that decay violates isospin conservation. has natural spin-parity low suggests JP=0+ assignment. sample corresponds to an integrated luminosity 91 fb−1 recorded by BABAR detector SLAC PEP-II asymmetric-energy storage ring.Received 11...
Searches for lepton-flavor-violating decays of a tau lepton to lighter mass and photon have been performed with the entire data set (963+/-7)x10{6} collected by BABAR detector near Upsilon(4S), Upsilon(3S) Upsilon(2S) resonances. The searches yield no evidence signals we upper limits on branching fractions B(tau{+/-}-->e{+/-}gamma)<3.3x10{-8} B(tau{+/-}-->mu{+/-}gamma)<4.4x10{-8} at 90% confidence level.
We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at PEP-II asymmetric Factory SLAC. This result uses additional sample Upsilon(4S) collected 2001, bringing data available to 32 x 10(6) BB macro pairs. select events which one meson is fully reconstructed a final state containing charmonium and flavor other determined from its decay products. The amplitude asymmetry, standard model proportional sin2 beta, derived time...
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...
We study the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ using $117\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected at $Y(4S)$ resonance with BABAR detector PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ asymmetric-energy storage ring. measure branching fractions $\mathcal{B}$...
We study the reaction e+e−→e+e−π0 in single tag mode and measure differential cross section dσ/dQ2 γγ∗→π0 transition form factor momentum transfer range from 4 to 40 GeV2. At Q2>10 GeV2 measured exceeds asymptotic limit predicted by perturbative QCD. The analysis is based on 442 fb−1 of integrated luminosity collected at PEP-II with BABAR detector e+e− center-of-mass energies near 10.6 GeV.16 MoreReceived 29 May 2009DOI:https://doi.org/10.1103/PhysRevD.80.052002©2009 American Physical Society
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...
A precise measurement of the cross section process e+ e- to pi+ pi- (gamma) from threshold an energy 3 GeV is obtained with initial state radiation (ISR) method using 232 fb^-1 data collected BABAR detector at center-of-mass energies near 10.6 GeV. The ISR luminosity determined a study leptonic mu+ mu- gamma (gamma). leading-order hadronic contribution muon magnetic anomaly calculated pi measured 1.8 (514.1 +-2.2(stat} +-3.1(syst}) x 10^{-10}.
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 present a measurement of the cross section process e(+)e(-)-->pi(+)pi(-)psi(2S) from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at SLAC PEP-II e(+)e(-) storage rings. The study is based on 298 fb(-1) data recorded with BABAR detector. A structure observed in not far above threshold, near 4.32 GeV. also investigate compatibility this Y(4260) previously reported by experiment.
We present results on time-dependent CP asymmetries in neutral B decays to several eigenstates. The measurements use a data sample of about 88 x 10(6) Upsilon(4S)-->B(-)B collected between 1999 and 2002 with the BABAR detector at PEP-II asymmetric-energy factory SLAC. study events which one meson is fully reconstructed final state containing charmonium other determined be either B(0) or B(-0) from its decay products. amplitude asymmetry, standard model proportional sin2beta, derived...
The e+e−→pp¯ cross section is determined over a range of pp¯ masses, from threshold to 4.5 GeV/c2, by studying the e+e−→pp¯γ process. data set corresponds an integrated luminosity 232 fb−1, collected with BABAR detector at PEP-II storage ring, e+e− center-of-mass energy 10.6 GeV. mass dependence ratio electric and magnetic form factors, |GE/GM|, measured for masses below 3 GeV/c2; its value found be significantly larger than 1 up 2.2 GeV/c2. We also measure J/ψ→pp¯ ψ(2S)→pp¯ branching...
A precise measurement of the cross section process $e^+e^-\toπ^+π^-(γ)$ from threshold to an energy 3GeV is obtained with initial-state radiation (ISR) method using 232fb$^{-1}$ data collected BaBar detector at $e^+e^-$ center-of-mass energies near 10.6GeV. The ISR luminosity determined a study leptonic $e^+e^-\toμ^+μ^-(γ)γ_{\rm ISR}$, which found agree next-to-leading-order QED prediction within 1.1%. for systematic uncertainty 0.5% in dominant $ρ$ resonance region. leading-order hadronic...
In a sample of $471\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected with the BABAR detector at PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ collider we study rare decays $B\ensuremath{\rightarrow}{K}^{(*)}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where ${\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ is either or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. We report results on partial branching fractions and isospin...
This paper reports measurements of processes: e+e−→γKS0K±π∓, e+e−→γK+K−π0, e+e−→γϕη, and e+e−→γϕπ0. The initial-state radiated photon allows to cover the hadronic final state in energy range from thresholds up ≈4.6 GeV. overall size data sample analyzed is 232 fb−1, collected by BABAR detector running at PEP-II e+e− storage ring. From Dalitz plot analysis KS0K±π∓ state, moduli, relative phase isoscalar isovector components e+e−→KK*(892) cross section are determined. Parameters ϕ ρ...
We search for the flavor-changing neutral-current decays $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, and invisible $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ via $B\ensuremath{\rightarrow}{K}^{(*)}J/\ensuremath{\psi}$ $B\ensuremath{\rightarrow}{K}^{(*)}\ensuremath{\psi}(2S)$, respectively, using a data sample of...
We present measurements of the flavor-changing neutral current decays B --> Kl+l- and K*l+l-, where l+l- is either an e+e- or mu+mu- pair. The data sample comprises 229 x 10^6 Y(4s) -->to BBbar collected with BaBar detector at PEP-II storage ring. Flavor-changing are highly suppressed in Standard Model their predicted properties could be significantly modified by new physics electroweak scale. measure branching fractions B(B Kll) = (0.34 +- 0.07 0.02) 10^{-6}, K*ll) (0.78^{+0.19}_{-0.17}...
We present a study of the decays B^{0,+} --> J/psi pi^+ pi^- pi^0 K^{0,+}, using 467 10^6 BBbar pairs recorded with BABAR detector. evidence for decay mode X(3872) omega, product branching fractions B(B^+ X(3872)K^+) B(X(3872) omega) =[0.6\pm0.2\stat \pm 0.1\syst ] 10^{-5}, and B(B^0 X(3872)K^0) =[0.6\pm0.3\stat 10^{-5}. A detailed mass distribution from favors negative-parity assignment.
In a search for $B\ensuremath{\rightarrow}c\overline{c}\ensuremath{\gamma}K$ decays with the BABAR detector, where $c\overline{c}$ includes $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$, $K$ ${K}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}_{S}^{0}$, ${K}^{*}(892)$, we find evidence $X(3872)\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\gamma}$ $X(3872)\ensuremath{\rightarrow}\ensuremath{\psi}(2S)\ensuremath{\gamma}$ $3.6\ensuremath{\sigma}$ $3.5\ensuremath{\sigma}$ significance,...
We search for evidence of a light scalar boson in the radiative decays Upsilon(2S) and Upsilon(3S) resonances: Upsilon(2S,3S)-->gammaA0, A0-->mu+mu-. Such particle appears extensions standard model, where CP-odd Higgs naturally couples strongly to b quarks. find no such processes mass range 0.212 < or = mA0 9.3 GeV samples 99 x 10(6) 122 collected by BABAR detector at SLAC PEP-II B factory set stringent upper limits on effective coupling quark A0. also limit dimuon branching fraction etab...
We study e+e−→J/ψ cc¯ by measuring the invariant mass distribution recoiling against fully reconstructed J/ψ decays, using 124 fb−1 of data collected at a center-of-mass energy 10.6 GeV with BABAR detector. observe signals for ηc(1S), χc0, and ηc(2S) in recoil distribution, thus confirming previous measurements. measure σ(e+e−→J/ψ+cc¯)B(cc¯→>2 charged) to be 17.6±2.8(stat)−2.1+1.5(syst) fb, 10.3±2.5(stat)−1.8+1.4(syst) 16.4±3.7(stat)−3.0+2.4(syst) fb cc¯=ηc(1S), ηc(2S), respectively.Received...