M. Barrett
A5059472867- 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
- Black Holes and Theoretical Physics
- Medical Imaging Techniques and Applications
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Corporate Taxation and Avoidance
- Nuclear Physics and Applications
- Taxation and Legal Issues
- Silicon and Solar Cell Technologies
- solar cell performance optimization
- Law, Economics, and Judicial Systems
- Auditing, Earnings Management, Governance
- Securities Regulation and Market Practices
- Photovoltaic Systems and Sustainability
Wilfrid Laurier University
2023
High Energy Accelerator Research Organization
2020-2022
St. Vincent's University Hospital
2020-2021
Wayne State University
2018-2020
University of Hawaiʻi at Mānoa
2012-2019
University of Birmingham
2004-2017
University of Hawaii System
2012-2017
The Edgbaston Hospital
2017
University of Virginia
2015
Brunel University of London
2007-2014
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...
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.
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}.
We search for the rare decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>B</a:mi><a:mo>+</a:mo></a:msup><a:mo stretchy="false">→</a:mo><a:msup><a:mi>K</a:mi><a:mo>+</a:mo></a:msup><a:mi>ν</a:mi><a:mover accent="true"><a:mi>ν</a:mi><a:mo stretchy="false">¯</a:mo></a:mover></a:math> in a <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mn>362</f:mn><f:mtext> </f:mtext><f:mtext>...
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.
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...
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 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}...
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...
We study the processes e+e−→2(π+π−)π0γ, 2(π+π−)ηγ, K+K−π+π−π0γ and K+K−π+π−ηγ with hard photon radiated from initial state. About 20 000, 4300, 5500, 375 fully reconstructed events, respectively, are selected 232 fb−1 of BABAR data. The invariant mass hadronic final state defines effective e+e− center-of-mass energy, so that obtained cross sections threshold to about 5 GeV can be compared corresponding direct measurements, currently available only for ηπ+π− ωπ+π− submodes e+e−→2(π+π−)π0...
We measure the branching fraction of B−→τ−¯ντ using full Υ(4S) data sample containing 772×106 B¯¯¯B pairs collected with Belle detector at KEKB asymmetric-energy e+e− collider. Events are tagged by reconstructing one B mesons decaying into hadronic final states, and candidates detected in recoil. find evidence for a significance 3.0 standard deviations including systematic errors B(B−→τ−¯ντ)=[0.72+0.27−0.25(stat)±0.11(syst)]×10−4.Received 16 November...
The BaBar detector operated successfully at the PEP-II asymmetric e+e− collider SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of systems, as well trigger, online offline computing, aspects event reconstruction since beginning data taking.
We search for the production of doubly charmed baryons in e+e− annihilations at or near a center-of-mass energy 10.58 GeV, data sample with an integrated luminosity 232 fb−1 recorded BABAR detector PEP-II storage ring Stanford Linear Accelerator Center. Ξ+cc final states Λ+cK−π+ and Ξ0cπ+, Ξ++cc Λ+cK−π+π+ Ξ0cπ+π+. find no evidence baryons.Received 18 May 2006DOI:https://doi.org/10.1103/PhysRevD.74.011103©2006 American Physical Society
We report the results of a search for bottomonium ground state eta_b(1S) in photon energy spectrum with sample (109 +/- 1) million Upsilon(3S) recorded at BABAR detector PEP-II B factory SLAC. observe peak E_gamma = 921.2 {+2.1} {-2.8} (stat) 2.4(syst) MeV significance 10 standard deviations. interpret observed as being due to monochromatic photons from radiative transition -> gamma eta_b(1S). This corresponds an mass $9388.9 {+3.1} {-2.3} 2.7(syst) MeV/c2. The hyperfine...
We report the results of a search for $Z(4430)^-$ decay to $J/\psi\pi^-$ or $\psi(2S)\pi^-$ in $B^{-,0}\to \jpsi\pi^- K^{0,+}$ and \psitwos \pi^- decays. The data were collected with BABAR detector at SLAC PEP-II asymmetric-energy $e^+e^-$ collider operating center mass energy 10.58 \gev, sample corresponds an integrated luminosity 413 fb$^{-1}$. Each $K\pi$ distribution exhibits clear $K^{\ast}(892)$ $K^{\ast}_2(1430)$ signals, efficiency-corrected spectrum is well-described by...
We present a measurement of angular observables, $P_4'$, $P_5'$, $P_6'$, $P_8'$, in the decay $B^0 \to K^\ast(892)^0 \ell^+ \ell^-$, where $\ell^+\ell^-$ is either $e^+e^-$ or $\mu^+\mu^-$. The analysis performed on data sample corresponding to an integrated luminosity $711~\mathrm{fb}^{-1}$ containing $772\times 10^{6}$ $B\bar B$ pairs, collected at $\Upsilon(4S)$ resonance with Belle detector asymmetric-energy collider KEKB. Four $P_{4,5,6,8}'$ are extracted five bins invariant mass...
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We present a measurement of the direct CP violating asymmetry in decay B0-->K+pi(-) using data sample 227x10(6) Upsilon(4S)-->BB decays collected with BABAR detector at PEP-II asymmetric-energy e(+)e(-) collider SLAC. observe total signal yield nK-(pi(+))+nK+(pi(-))=1606+/-51 and measure (nK-(pi(+))-nK+(pi(-)))/(nK-(pi(+))+nK+(pi(-)))=-0.133+/-0.030(stat)+/-0.009(syst). The probability observing such an absence violation is 1.3x10(-5), corresponding to 4.2 standard deviations.
The process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$ has been studied at a center-of-mass energy near the $\ensuremath{\Upsilon}(4S)$ resonance using $89.3\text{ }\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample collected with BABAR detector PEP-II collider. From measured $3\ensuremath{\pi}$ mass spectrum we have obtained products of branching fractions for...
We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with photon radiated from initial state. About 20,000, 33,000 4,000 fully reconstructed events, respectively, have been selected 232 fb-1 of BaBar data. The invariant mass hadronic final state defines effective e+e- center-of-mass energy, so that these data can be compared corresponding direct measurements. From 3(pi+pi-), 2(pi+pi-pi0) 2(pi+pi-) spectra, cross sections for are measured energies...
We study the initial-state-radiation processes ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\gamma}$ and ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}$ using an integrated luminosity of $232\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected at $\ensuremath{\Upsilon}(4S)$ mass with BABAR...
We observe a new Ds meson with mass (2856.6±1.5stat±5.0syst) MeV/c2 and width (48±7stat±10syst) decaying into D0K+ D+K0S. In the same distributions, we also broad structure (2688±4stat±3syst) (112±7stat±36syst) MeV/c2. To obtain this result, use 240 fb−1 of data recorded by BABAR detector at PEP-II asymmetric-energy e+e− storage rings Stanford Linear Accelerator Center running center-of-mass energies near 10.6 GeV.Received 27 July 2006DOI:https://doi.org/10.1103/PhysRevLett.97.222001©2006...
We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from initial state. About 60,000 fully reconstructed events have been selected 89 $fb^{-1}$ of BaBar data. The invariant mass hadronic final state defines effective \epem center-of-mass energy, so that these data can be compared corresponding direct $e^+e^-$ measurements. From $4\pi$-mass spectrum, cross section for $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured energies 0.6 to 4.5 $GeV/c^2$. uncertainty in...