0000000000048442

AUTHOR

Y. I. Skovpen

showing 35 related works from this author

Measurement of theB0→K2*(1430)0γandB+→K2*(1430)+γbranching fractions

2004

We have investigated the exclusive, radiative B meson decays to K2*(1430) in 89* 10^6 BBbar events with the BaBar detector at the PEP-II storage ring. We measure the branching fractions BR(B0 -> K2*(1430)0 gamma) = (1.22 +-0.25 +-0.10)*10^(-5) and BR(B+ -> K2*(1430)+ gamma) = (1.45 +-0.40 +-0.15) * 10^(-5), where the first error is statistical and the second systematic. In addition, we measure the CP-violating asymmetry ACP(B0 -> K2*(1430)0 gamma) = -0.08 +- 0.15 +- 0.01.

PhysicsNuclear physicsNuclear and High Energy Physics010308 nuclear & particles physicsBranching fractionElectron–positron annihilation0103 physical sciencesAnalytical chemistryB meson010306 general physicsBranching (polymer chemistry)01 natural sciencesParticle identificationPhysical Review D
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Measurements of the Mass and Width of theηcMeson and of anηc(2S)Candidate

2004

The mass m(eta(c)) and total width Gamma(eta(c))(tot) of the eta(c) meson have been measured in two-photon interactions at the SLAC e(+)e(-) asymmetric B Factory with the BABAR detector. With a sample of approximately 2500 reconstructed eta(c)-->K(0)(S)K+/-pi(-/+) decays in 88 fb(-1) of data, the results are m(eta(c))=2982.5+/-1.1(stat)+/-0.9(syst) MeV/c(2) and Gamma(eta(c))(tot)=34.3+/-2.3(stat)+/-0.9(syst) MeV/c(2). Using the same decay mode, a second resonance with 112+/-24 events is observed with a mass of 3630.8+/-3.4(stat)+/-1.0(syst) MeV/c(2) and width of 17.0+/-8.3(stat)+/-2.5(syst) MeV/c(2). This observation is consistent with expectations for the eta(c)(2S) state.

Quantum chromodynamicsPhysicsMeson010308 nuclear & particles physicsAnalytical chemistryGeneral Physics and AstronomyResonance01 natural sciencesB-factoryNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsPhysical Review Letters
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Limit on theB0→ρ0ρ0Branching Fraction and Implications for the Cabibbo-Kobayashi-Maskawa Angleα

2005

The authors search for the decay B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} in a data sample of about 227 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They find no significant signal and set an upper limit of 1.1 x 10{sup -6} at 90% CL on the branching fraction. As a result, the uncertainty due to penguin contributions on the CKM unitarity angle {alpha} measured in B {yields} {rho}{rho} decays is 11{sup o} at 68% CL.

PhysicsParticle physicsUnitarity010308 nuclear & particles physicsBranching fractionCabibbo–Kobayashi–Maskawa matrixElectron–positron annihilationGeneral Physics and Astronomy01 natural scienceslaw.inventionNuclear physicsParticle decaylaw0103 physical sciencesLimit (mathematics)010306 general physicsColliderBar (unit)Physical Review Letters
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Measurement of the Inclusive Charmless Semileptonic Branching Ratio ofBMesons and Determination of|Vub|

2004

We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 x 10(6) (-)BB events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson. The number of signal events is extracted from the mass distribution of the hadronic system accompanying the lepton and is used to determine the ratio of branching fractions B((-)B-->X(u)lnu;)/B((-)B-->Xlnu;)=[2.06+/-0.25(stat)+/-0.23(syst)+/-0.36(theo)]x10(-2). Using the measured branching fraction for inclusive semileptonic B decays, we find B((-)B-->X(u)lnu;)…

PhysicsHigh energyParticle physics010308 nuclear & particles physicsBranching fractionElectron–positron annihilationHadronGeneral Physics and Astronomy01 natural sciencesNuclear physics0103 physical sciencesMass spectrumMatrix elementB meson010306 general physicsLeptonPhysical Review Letters
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Search for flavor-changing neutral current and lepton-flavor violating decays of D-0 -> l(+)l(-)

2004

We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\to\mu^+\mu^-$, and the lepton-flavor violating decay $\Dz\to e^\pm\mu^\mp$. The measurement is based on $122 {fb}^{-1}$ of data collected by the \babar detector at the PEP-II asymmetric $e^+e^-$ collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90 % confidence level, are $1.2\times 10^{-6}$ for $\Dz\to e^+e^-$, $1.3\times 10^{-6}$ for $\Dz\to\mu^+\mu^-$, and $8.1\times 10^{-7}$ for $\Dz\to e^\pm\mu^\mp$.

OptimizationParticle physicsLepton-flavor violating (LFV)Electron–positron annihilationBABARCharged particleGeneral Physics and Astronomy-Standard model (SM)Lambda baryon01 natural sciencesPARTICLE PHYSICS; PEP2; BABARHigh Energy Physics - ExperimentNONuclear physicsSilicon microstrip detector0103 physical sciencesPEP2010306 general physicsDETECTOR; BABAR; SLACDETECTORFlavorProbabilityPhysicsNeutral current010308 nuclear & particles physicsEnergy dissipationFlavor-changing neutral currentColliding beam acceleratorMicrostrip deviceHEPFlavor-changing neutral current (FCNC)Drift chamberPARTICLE PHYSICSHigh Energy Physics::ExperimentParticle detectorSLACLepton
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Measurement of the branching fractions for inclusiveB−andB¯0decays to flavor-taggedD,Ds, andΛc

2004

We report on the inclusive branching fractions of $B^-$ and of ${\bar B}^0$ mesons decaying to ${D^0 X}$, ${{\bar D}^0 X}$, ${D^+ X}$, ${D^- X}$, ${D_s^+ X}$, ${D_s^- X}$, ${\Lambda_c^+ X}$, ${{\bar \Lambda}_c^- X}$, based on a sample of 88.9 million $B \bar B$ events recorded with the $BABAR$ detector at the $\Upsilon(4S)$ resonance. Events are selected by completely reconstructing one $B$ and searching for a reconstructed charmed particle in the rest of the event. We measure the number of charmed and of anti-charmed particles per $B$ decay and derive the total charm yield per $B^-$ decay, $n_c^- = 1.313 \pm 0.037 \pm 0.062 ^{+0.063}_{-0.042} $, and per ${\bar B}^0$ decay, $n_c^0 = 1.276 \…

PhysicsNuclear and High Energy PhysicsParticle physicsMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilationResonanceLambda01 natural sciencesParticle identificationNuclear physics0103 physical sciencesB meson010306 general physicsBar (unit)Physical Review D
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Measurement of the Spin of the Ω− Hyperon

2006

A measurement of the spin of the Omega(-) hyperon produced through the exclusive process Xi(c)(0)--Omega(-)K(+) is presented using a total integrated luminosity of 116 fb(-1) recorded with the BABAR detector at the e(+)e(-) asymmetric-energy B factory at SLAC. Under the assumption that the Xi(c)(0) has spin 1/2, the angular distribution of the Lambda from Omega(-)--LambdaK(-) decay is inconsistent with all half-integer Omega(-) spin values other than 3/2. Lower statistics data for the process Omega(c)(0)--Omega(-)pi(+) from a 230 fb(-1) sample are also found to be consistent with Omega(-) spin 3/2. If the Xi(c)(0) spin were 3/2, an Omega(-) spin of 5/2 could not be excluded.

Particle physicsBABARmedia_common.quotation_subjectElectron–positron annihilationGeneral Physics and AstronomyLIFETIMELambda01 natural sciencesOmegaAsymmetryLuminosityNuclear physicsParticle decay0103 physical sciencesSDG 7 - Affordable and Clean Energy010306 general physicsmedia_commonSpin-½Physics/dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energy010308 nuclear & particles physicsHyperonParticle physicsHEPHigh Energy Physics::ExperimentSLACFísica de partículesExperimentsLIFETIME; BABAR; SLAC
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Search for the Radiative DecaysB→ργandB0→ωγ

2004

A search for the exclusive radiative decays B {yields} {rho}(770){gamma} and B{sup 0} {yields} {omega}(782){gamma} is performed on a sample of about 84 million B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. No significant signal is seen in any of the channels. We set upper limits on the branching fractions {Beta} of {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 1.2 x 10{sup -6}, {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) < 2.1 x 10{sup -6}, and {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6} at 90% confidence level (C.L.). Using the assumption that {Lambda}(B {yields} {rho}{gamma}) = {Lambda}(B{sup +} {yields} …

Physics010308 nuclear & particles physicsBranching fractionElectron–positron annihilationRadiative decayGeneral Physics and Astronomy01 natural sciencesOmegaCrystallography0103 physical sciencesRadiative transferB mesonAtomic physics010306 general physicsPhysical Review Letters
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Branching fraction measurements ofB→ηcKdecays

2004

We study the decays B{sup +} {yields} {eta}{sub c}K{sup +} and B{sup 0} {yields} {eta}{sub c}K{sup 0}, where the {eta}{sub c} is reconstructed in the K{sub S}{sup 0} K{sup {+-}} {pi}{sup {-+}} and K{sup +}K{sup -} {pi}{sup 0} decay modes. Results are based on a sample of 86 million B{bar B} pairs collected with the BABAR detector at the SLAC e{sup +}e{sup -} B Factory. We measure the branching fractions {Beta}(B{sup +} {yields} {eta}{sub c}K{sup +}) = (1.34 {+-} 0.09 {+-} 0.13 {+-} 0.41) x 10{sup -3} and {Beta}(B{sup 0} {yields} {eta}{sub c}K{sup 0}) = (1.18 {+-} 0.16 {+-} 0.13 {+-} 0.37) x 10{sup -3}, where the first error is statistical, the second is systematic, and the third reflects th…

PhysicsNuclear and High Energy PhysicsParticle decayCrystallography010308 nuclear & particles physicsBranching fractionElectron–positron annihilation0103 physical sciencesB mesonAtomic physics010306 general physics01 natural sciencesPhysical Review D
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Measurement of theB→Xsℓ+ℓ−Branching Fraction with a Sum over Exclusive Modes

2004

We present a preliminary measurement of time-dependent We measure the branching fraction for the flavor-changing neutral-current process B -> Xs l+ l- with a sample of 89 x 10^6 Upsilon(4S) -> BBbar events recorded with the BaBar detector at the PEP-II e+e- storage ring. The final state is reconstructed from e+e- or mu+mu- pairs and a hadronic system consisting of one K or K0s and up to two pions, with at most one pi0. We observe a signal of 40 +/- 10(stat) +/- 2(syst) events and extract the inclusive branching fraction B(B -> Xs l+ l-) = (5.6 +/- 1.5(stat) +/- 0.6(exp syst) +/- 1.1(model syst)) x 10^-6 for mll > 0.2 GeV/c^2.

PhysicsParticle physics010308 nuclear & particles physicsBranching fractionElectron–positron annihilationHadronGeneral Physics and Astronomy01 natural sciencesParticle decayPair productionPion0103 physical sciencesB meson010306 general physicsPhysical Review Letters
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Observation ofΥ(4S)Decays toπ+π−Υ(1S)andπ+π−Υ(2S)

2006

We present the first measurement of Υ(4S) decays to π+π-Υ(1S) and π+π-Υ(2S) based on a sample of 230×106Υ(4S) mesons collected with the BABAR detector. We measure the product branching fractions B(Υ(4S)→π+π-Υ(1S))×B(Υ(1S)→μ+μ-)=(2.23±0.25stat±0.27syst)×10-6 and B(Υ(4S)→π+π-Υ(2S))×B(Υ(2S)→μ+μ-)=(1.69±0.26stat±0.20syst)×10-6, from which we derive the partial widths Γ(Υ(4S)→π+π-Υ(1S))=(1.8±0.4)  keV and Γ(Υ(4S)→π+π-Υ(2S))=(2.7±0.8)  keV.

PhysicsParticle decayParticle physicsMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilation0103 physical sciencesGeneral Physics and Astronomy010306 general physics01 natural sciencesPhysical Review Letters
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Search for Radiative Penguin DecaysB+→ρ+γ,B0→ρ0γ, andB0→ωγ

2005

A search for the decays B {yields} {rho}(770){gamma} and B{sup 0} {yields} {omega}(782) is performed on a sample of 211 million {Upsilon}(4S) {yields} B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) < 1.8 x 10{sup -6}, {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 0.4 x 10{sup -6}, and {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6} at the 90% confidence level (C.L.). We use the quark model to limit the combined branching fraction {bar {Beta}}[B {yields} ({rho}/{omega})…

Physics010308 nuclear & particles physicsBranching fractionElectron–positron annihilationQuark modelRadiative decayGeneral Physics and Astronomy01 natural sciencesOmegaCrystallography0103 physical sciencesRadiative transferB meson010306 general physicsPhysical Review Letters
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Improved Measurement ofCPAsymmetries inB0→(cc¯)K0(*)Decays

2005

We present results on time-dependent $CP$ asymmetries in neutral $B$ decays to several $CP$ eigenstates. The measurements use a data sample of about 227 million $\Upsilon$(4S) $\rightarrow B\overline{B}$ decays collected by the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. The amplitude of the CP asymmetry, sin2$\Beta$ in the Standard Model, is derived from decay-time distributions from events in which one neutral $B$ meson is fully reconstructed in a final state containing a charmonium meson and the other $B$ meson is determined to be either a $B^0$ or $\overline{B}^0$ from its decay products. We measure sin2$\Beta$ = 0.722 $\pm$ 0.040 (stat.) $\pm$ 0.23 (syst.) in ag…

PhysicsParticle physicsMeson010308 nuclear & particles physicsElectron–positron annihilationmedia_common.quotation_subjectHigh Energy Physics::PhenomenologyGeneral Physics and Astronomy01 natural sciencesMeasure (mathematics)AsymmetryStandard ModelNuclear physicsAmplitude0103 physical sciencesCP violationHigh Energy Physics::ExperimentB meson010306 general physicsmedia_commonPhysical Review Letters
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Limits on the decay-rate difference of neutralBmesons and onCP,T, andCPTviolation inB0B0oscillations

2004

Using events in which one of two neutral-B mesons from the decay of an {Upsilon}(4S) resonance is fully reconstructed, we set limits on the difference between the decay rates of the two neutral-B mass eigenstates and on CP, T, and CPT violation in B{sup 0}{bar B}{sup 0} mixing. The reconstructed decays, comprising both CP and flavor eigenstates, are obtained from 88 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine six independent parameters governing oscillations ({Delta}m, {Delta}{Lambda}/{Lambda}), CPT and CP violation (Re z, Im z), and CP and T violation (Im {lambda}{sub CP}, |q/p|), where {la…

PhysicsNuclear and High Energy PhysicsParticle physicsMeson010308 nuclear & particles physicsResonanceLambda01 natural sciencesStandard ModelB-factoryNuclear physics0103 physical sciencesCP violationB meson010306 general physicsBar (unit)Physical Review D
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Measurement of Branching Fractions and Charge Asymmetries inBDecays to anηMeson and aK*Meson

2006

We present measurements of branching fractions and charge asymmetries for the decays B-->etaK*, where K* indicates a spin 0, 1, or 2 Kpi system. The data sample corresponds to 344x10(6) BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+ e- collider at SLAC. We measure the branching fractions (in units of 10(-6): B(B0-->etaK*0(892))=16.5+/-1.1+/-0.8, B(B+-->etaK*+(892))=18.9+/-1.8+/-1.3, B(B0-->eta(Kpi)0*0)=11.0+/-1.6+/-1.5, B(B+-->eta(Kpi)0*+)=18.2+/-2.6+/-2.6, B(B0-->etaK2*0(1430))=9.6+/-1.8+/-1.1, and B(B+-->etaK2*+(1430))=9.1+/-2.7+/-1.4. We also determine the charge asymmetries for all decay modes.

PhysicsParticle physicsMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilationEta mesonGeneral Physics and AstronomyBranching (polymer chemistry)01 natural sciencesParticle decayPair production0103 physical sciences010306 general physicsPhysical Review Letters
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Search for the DecayB+→K+νν¯

2005

We search for the rare flavor-changing neutral-current decay ${B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in a data sample of $82\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the BABAR detector at the PEP-II $B$-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-$B$ decay. Using these two independent samples we obtain a combined limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})l5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at the 90% confidence level. In addition, by…

PhysicsParticle physicsPion010308 nuclear & particles physicsElectron–positron annihilation0103 physical sciencesHadronIndependent samplesGeneral Physics and Astronomy010306 general physics01 natural sciencesReconstruction methodPhysical Review Letters
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Measurement of theB→πlνBranching Fraction and Determination of|Vub|with TaggedBMesons

2006

We report a measurement of the B ->pi center dot nu branching fraction based on 211 fb(-1) of data collected with the BABAR detector. We use samples of B-0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay and combine the results assuming isospin symmetry to obtain B(B-0 ->pi(-)center dot(+)nu)=(1.33 +/- 0.17(stat)+/- 0.11(syst))x10(-4). We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find vertical bar V-ub …

PhysicsQuantum chromodynamicsParticle physicsMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilationHigh Energy Physics::PhenomenologyGeneral Physics and Astronomy01 natural sciencesNuclear physicsParticle decayPionIsospin0103 physical sciencesHigh Energy Physics::ExperimentB meson010306 general physicsPhysical Review Letters
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Observation ofe+e−Annihilation into theC=+1Hadronic Final Statesρ0ρ0andϕρ0

2006

The authors report the first observation of e{sup +}e{sup -} annihilations into states of positive C-parity, namely {rho}{sup 0}{rho}{sup 0} and {phi}{rho}{sup 0}. The two states are observed in the {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} and K{sup +}K{sup -} {pi}{sup +}{pi}{sup -} final states, respectively, in a data sample of 225 fb{sup -1} collected by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage rings at energies near {radical}s = 10.58 GeV. The distributions of cos {theta}*, where {theta}* is the center-of-mass polar angle of the {phi} meson or the forward {rho}{sup 0} meson, suggest production by two-virtual-photon annihilation. They measure cross sections within …

PhysicsParticle physicsAnnihilationMeson010308 nuclear & particles physicsElectron–positron annihilationHadronGeneral Physics and Astronomy01 natural sciencesCrystallographyAngular distributionPair productionTheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY0103 physical sciencesHigh Energy Physics::ExperimentProduction (computer science)010306 general physicsBhabha scatteringPhysical Review Letters
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Search forD0−D¯0mixing using semileptonic decay modes

2004

Based on an 87-fb{sup -1} data set collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, a search for D{sup 0}-D-bar{sup 0} mixing has been made using the semileptonic decay modes D*{sup +}{yields}{pi}{sup +}D{sup 0}, D{sup 0}{yields}K{sup (}*{sup )}e{nu} (+c.c.). The use of these modes allows unambiguous flavor tagging and a combined fit of the D{sup 0} decay time and D*{sup +}-D{sup 0} mass difference ({delta}M) distributions. The high-statistics sample of unmixed semileptonic D{sup 0} decays is used to model the {delta}M distribution and time dependence of mixed events directly from the data. Neural networks are used to select events and reconstruct the D{sup 0}. A r…

Semileptonic decayPhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsElectron–positron annihilationElectron01 natural sciencesParticle identificationB-factoryDistribution (mathematics)0103 physical sciencesInvariant mass010306 general physicsMixing (physics)Physical Review D
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Measurement of branching fractions and charge asymmetries for exclusive B decays to charmonium

2005

We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/Psi, Psi(2S) and Chi_c1, and the light meson is either K or K*. We use a sample of about 124 million BBbar events collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.

Molecular dynamicElectron–positron annihilationHigh Energy Physics::LatticeBABARNuclear TheoryGeneral Physics and Astronomy01 natural sciences13.25.Hw 11.30.Er 12.15.HhElectron positronlaw.inventionHigh Energy Physics - ExperimentHigh Energy Physics - Experiment (hep-ex)Mathematical modellawB mesons; charm particles; chi mesons; kaon production; meson hadronic decay; psi mesons[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]PEP2B mesonNuclear ExperimentConstraint theorymedia_commonPhysicsAnnihilationEnergy dissipationSettore FIS/01 - Fisica SperimentaleQuarkonium strange mesonParticle physicsMESONSpair production [B]PARTICLE PHYSICSBranching fractionSLACOptimizationParticle physicsSiliconMesonmedia_common.quotation_subjectFOS: Physical sciencesCharged particleAnnihilationAsymmetryPARTICLE PHYSICS; PEP2; BABARNuclear physics0103 physical sciencesbranching ratio [B0]Colliding beamsMESONS; BABAR; SLACBeam directionResistive plate chambers (RPC)010306 general physicshadronic decay [B]Calorimeter010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyParticle acceleratorHEPbranching ratio [B+]Quantum theoryElectromagnetic calorimeters (EMC)High Energy Physics::ExperimentFísica de partículesExperimentsStorage ring
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Measurement of branching fractions and rate asymmetries in the rare decays B -> K((*))l(+)l(-)

2012

In a sample of 471 million BB events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B -> K(*) l+ l-, where l+ l- is either e+e- or mu+mu-. We report results on partial branching fractions and isospin asymmetries in seven bins of di-lepton mass-squared. We further present CP and lepton-flavor asymmetries for di-lepton masses below and above the J/psi resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.

Nuclear and High Energy PhysicsParticle physicsB-DECAYSElectron–positron annihilationNuclear TheoryB-meson decays; semileptonic B-meson decaysBranching (polymer chemistry)01 natural sciencesResonance (particle physics)law.inventionStandard ModelHigh Energy Physics - ExperimentNuclear physicsB-meson decaylaw0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]PACS: 13.20.He010306 general physicsColliderPhysics010308 nuclear & particles physicsLeptons (Física nuclear)High Energy Physics::PhenomenologyParticle physicsB-meson decaysHEP3. Good healthLeptons (Nuclear physics)IsospinBaBarHigh Energy Physics::Experimentsemileptonic B-meson decaysSDG 6 - Clean Water and SanitationFísica de partículesExperiments
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Limits onD0−D¯0Mixing andCPViolation from the Ratio of Lifetimes for Decay toK−π+,K−K+, andπ−π+

2003

We present a measurement of D0-macro D0 mixing parameters using the ratios of lifetimes extracted from samples of D0 mesons decaying to K-pi(+), K-K+, and pi(-)pi(+). Using 91 fb(-1) of data collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, we obtain a value Y=[0.8+/-0.4(stat.)(+0.5)(-0.4)(syst.)]%, which, in the limit of CP conservation, corresponds to the mixing parameter y=Delta Gamma/2 Gamma. Using the difference in lifetimes of D0 and macro D0 mesons, we obtain the CP-violation parameter Delta Y=[-0.8+/-0.6(stat.)+/-0.2(syst.)]%.

PhysicsMeson010308 nuclear & particles physicsElectron–positron annihilationAnalytical chemistryGeneral Physics and AstronomyValue (computer science)01 natural sciencesB-factoryNuclear physicsParticle decay0103 physical sciencesPiCP violationHigh Energy Physics::Experiment010306 general physicsMixing (physics)Physical Review Letters
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Study of thee+e−→π+π−π0process using initial state radiation withBABAR

2004

The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19…

PhysicsNuclear and High Energy PhysicsMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilationAnalytical chemistryRadiation7. Clean energy01 natural sciencesOmegaNuclear physics0103 physical sciencesMass spectrumPi010306 general physicsBhabha scatteringPhysical Review D
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Search forB±→[K∓π±]DK±and Upper Limit on theb→uAmplitude inB±→DK±

2004

We search for B±→[K∓π±]DK± decays, where [K∓π±]D indicates that the K∓π± pair originates from the decay of a D0 or D 0. Results are based on 120×106 Υ(4S)→BB decays collected with the BABAR detector at SLAC. We set an upper limit on the ratio RKπ≡ [Γ(B+→[K-π+]DK+)+Γ(B-→[K+π-]DK-)]/[Γ(B+→[K+π-]DK+)+Γ(B-→[K-π+]DK-)]<0.026 (90%   C.L.). This constrains the amplitude ratio rB≡ |A(B-→D 0K-)/A(B-→D0K-)|<0.22 (90% C.L.), consistent with expectations. The small value of rB favored by our analysis suggests that the determination of the Cabibbo-Kobayashi-Maskawa phase γ from B→DK will be difficult.

Physics010308 nuclear & particles physicsElectron–positron annihilationAnalytical chemistryGeneral Physics and AstronomyValue (computer science)Width ratio01 natural sciencesAmplitude ratioParticle decayAmplitudeClassical mechanics0103 physical sciencesLimit (mathematics)010306 general physicsPhysical Review Letters
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Measurements ofCP-Violating Asymmetries inB0→Ks0π0Decays

2007

The authors present measurements of CP-violating asymmetries in the decay B{sup 0} {yields} a{sub 1}{sup {+-}}(1260){pi}{sup {-+}} with a{sub 1}{sup {+-}}(1260) {yields} {pi}{sup {-+}}{pi}{sup {+-}}{pi}{sup {+-}}. The data sample corresponds to 384 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric B-factory at SLAC. They measure the CP-violating asymmetry {Alpha}{sub CP}{sup a{sub 1}{pi}} = -0.07 {+-} 0.07 {+-} 0.02, the mixing-induced CP violation parameter S{sub a{sub 1}{pi}} = 0.37 {+-} 0.21 {+-} 0.07, the direct Cp violation parameter C{sub a{sub 1}{pi}} = -0.10 {+-} 0.15 {+-} 0.09, and the parameters {Delta}C{sub a{sub 1}{pi}} = 0.26 {+-} 0.15 {+-} 0…

PhysicsParticle physicsUnitarity010308 nuclear & particles physicsmedia_common.quotation_subjectElectron–positron annihilationGeneral Physics and Astronomy01 natural sciencesAsymmetryB-factoryNuclear physicsParticle decayCrystallography0103 physical sciencesCP violation010306 general physicsmedia_commonPhysical Review Letters
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Measurements of the branching fractions and bounds on the charge asymmetries of charmless three-body charged B decays.

2003

We present measurements of branching fractions and charge asymmetries for charmless B-meson decays to three-body final states of charged pions and kaons. The analysis uses 81.8 fb^-1 of data collected at the Upsilon(4S) resonance with the BaBar detector at the SLAC PEP-II asymmetric B Factory. We measure the branching fractions B(B+ -&gt; pi+ pi- pi+) = (10.9 +/- 3.3 +/- 1.6) x 10^-6, B(B+ -&gt; K+ pi- pi+) = (59.1 +/- 3.8 +/- 3.2) x 10^-6, and B(B+ -&gt; K+ K- K+) = (29.6 +/- 2.1 +/- 1.6) x 10^-6, and provide 90% C.L. upper limits for other decays. We observe no charge asymmetries for these modes.

Particle physicsMesonBABARHadronCharged particleGeneral Physics and AstronomyFOS: Physical sciencesElementary particlePARTICLE PHYSICS; PEP2; BABAR01 natural sciencesHigh Energy Physics - ExperimentNuclear physicsParticle decayHigh Energy Physics - Experiment (hep-ex)PionSEARCH0103 physical sciencesPEP2[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]B meson010306 general physicsProbabilityPhysics010308 nuclear & particles physicsBranching fractionCerenkov counterComputer simulationB-factoryMonte Carlo methodParticle beamNuclear physicPARTICLE PHYSICSBranching fractionStorage ringParticle beam trackingPhysical review letters
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Measurement of Time-DependentCP-Violating Asymmetries inB0→ϕKS0,K+K−KS0, andη′KS0Decays

2004

We present an improved measurement of $CP$-violation parameters in ${B}^{0}\ensuremath{\rightarrow}\ensuremath{\phi}{K}_{S}^{0}$, ${K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0}$, and ${\ensuremath{\eta}}^{\ensuremath{'}}{K}_{S}^{0}$ decays based on a $140\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral $B$ meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying $B$ meson is identified from its decay products. $CP$-violation parameters for each of the three modes are obtained from…

PhysicsParticle physicsMeson010308 nuclear & particles physicsElectron–positron annihilationmedia_common.quotation_subjectCenter (category theory)General Physics and AstronomyResonance01 natural sciencesAsymmetryB-factoryStandard ModelNuclear physicsParticle decayKEKB0103 physical sciencesPiCP violationB mesonHigh Energy Physics::Experiment010306 general physicsmedia_commonPhysical Review Letters
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DirectCPViolating Asymmetry inB0→K+π−Decays

2004

We present an updated search for direct CP violation in the decay B0 -> K+pi-. Using 227 million Y(4S) -> BBbar decays collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we observe a total signal yield of n(K-pi+) + n(K+pi-) = 1606 +- 51 decays and measure the asymmetry [n(K-pi+)-n(K+pi-)]/[n(K-p+-)+n(K+pi-)] = -0.133+-0.030 (stat) +- 0.009 (syst). This measurement establishes direct CP violation in the B0 meson system at the level of 4.2 standard deviations.

PhysicsParticle physicsMeson010308 nuclear & particles physicsElectron–positron annihilationHadronGeneral Physics and AstronomyElementary particle01 natural sciencesNuclear physicsParticle decayPion0103 physical sciencesCP violationB meson010306 general physicsPhysical Review Letters
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Search forB0Decays to Invisible Final States and toνν¯γ

2004

We establish upper limits on branching fractions for B0 decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for B0 decays to nunugamma. Within the standard model, these decays have branching fractions that are below current experimental sensitivity, but various models of physics beyond the standard model predict significant contributions from these channels. Using 88.5 x 10(6) BB pairs collected at the Upsilon(4S) resonance by the BABAR experiment at the PEP-II e(+)e- storage ring at the Stanford Linear Accelerator Center, we establish upper limits at the 90% confidence level of 22 x 10(-5) for the branching fraction of B0-->i…

PhysicsParticle physics010308 nuclear & particles physicsBranching fractionPhysics beyond the Standard ModelGeneral Physics and AstronomyBaBar experimentParticle acceleratorObservable01 natural sciencesUpper and lower boundslaw.inventionNuclear physicslaw0103 physical sciencesLarge extra dimensionB meson010306 general physicsPhysical Review Letters
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Measurement of the Time-DependentCPAsymmetry in theB0→ϕK0Decay

2004

The authors present a measurement of the time-dependent CP asymmetry for the neutral B-meson decay B{sup 0} {yields} {phi} K{sup 0}. They use a sample of approximately 114 million B-meson pairs taken at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. They reconstruct the CP eigenstates {phi}K{sub S}{sup 0} and {phi}K{sub L}{sup 0} where {phi} {yields} K{sup +}K{sup -}, K{sub S}{sup 0} {yields} {pi}{sup +}{pi}{sup -}, and K{sub L}{sup 0} is observed via its hadronic interactions. The other B meson in the event is tagged as either a B{sup 0} or {bar B}{sup 0} from its decay products. The values of the CP-violation parameters are S{sub {phi}K} = 0.47 …

PhysicsParticle physics010308 nuclear & particles physicsElectron–positron annihilationmedia_common.quotation_subjectHadronGeneral Physics and AstronomyResonance01 natural sciencesAsymmetryCrystallographyParticle decay0103 physical sciencesCP violationB meson010306 general physicsmedia_commonPhysical Review Letters
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Study ofB→DsJ(*)+D¯(*)Decays

2004

We report a study of D-sJ(*)(2317)(+) and D-sJ(2460)(+) meson production in B decays. We observe the decays B+--> D-sJ((*)+)(D) over bar ((*)0) and B-0 --> DsJ(*)+D(*)- with the subsequent decays D-sJ(*)(2317)(+)-->D(s)(+)pi(0), D-sJ(2460)(+)-->D(s)(+)gamma, and D-sJ(2460)(+)-->D(s)(*+)pi(0). Based on a data sample of 122.1x10(6) B(B) over bar pairs collected with the BABAR detector at the PEP-II B factory, we obtain branching fractions for these modes, including the previously unseen decays B-->(DsJ(*)+D*). In addition, we perform an angular analysis of D-sJ(2460)(+)-->D(s)(+)gamma decays to test the different D-sJ(2460)(+) spin hypotheses.

Nuclear physicsPhysicsMeson production010308 nuclear & particles physicsElectron–positron annihilation0103 physical sciencesAnalytical chemistryGeneral Physics and Astronomy010306 general physics01 natural sciencesB-factoryPhysical Review Letters
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Observation of the rare decayB+→K+π0π0and measurement of the quasi-two-body contributionsB+→K*(892)+π0,B+→f0(980)K+, andB+→χc0K+

2011

We report an analysis of charmless hadronic decays of charged B mesons to the final state K{sup +}{pi}{sup 0}{pi}{sup 0}, using a data sample of (470.9 {+-} 2.8) x 10{sup 6} B{bar B} events collected with the BABAR detector at the {Gamma}(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be {Beta}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = (16.2 {+-} 1.2 {+-} 1.5) x 10{sup -6} and A{sub CP}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = -0.06 {+-} 0.06 {+-} 0.04, where the uncertainties are statistical and systematic, respectively. Add…

PhysicsNuclear and High Energy PhysicsMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilationHadronDalitz plot01 natural sciencesParticle decayCrystallographyTheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY0103 physical sciencesB mesonAtomic physics010306 general physicsDimensionless quantityPhysical Review D
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Bound on the Ratio of Decay Amplitudes forB¯0→J/ψK*0andB0→J/ψK*0

2004

We have measured the time-dependent decay rate for the process B→J/ψK*0(892) in a sample of about 88×106 Υ(4S)→BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In this sample we study flavor-tagged events in which one neutral B meson is reconstructed in the J/ψK*0 or J/ψK *0 final state. We measure the coefficients of the cosine and sine terms in the time-dependent asymmetries for J/ψK*0 and J/ψK *0, find them to be consistent with the standard model expectations, and set upper limits at 90% confidence level (C.L.) on the decay amplitude ratios |A(B 0→J/ψK*0)|/|A(B0→J/ψK*0)|<0.26 and |A(B0→J/ψK *0)|/|A(B 0→J/ψK *0)|<0.32. For a single ratio of w…

PhysicsParticle physicsAmplitude010308 nuclear & particles physicsQuantum mechanics0103 physical sciencesGeneral Physics and AstronomyCP violationB meson010306 general physics01 natural sciencesStandard ModelB-factoryPhysical Review Letters
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Observation ofB0Meson Decay toa1±(1260)π∓

2006

We present a measurement of the branching fraction of the decay B-0 -> a(1)(+/-)(1260)pi(-/+) with a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-). The data sample corresponds to 218x10(6) B (B) over bar pairs produced in e(+)e(-) annihilation through the Upsilon(4S) resonance. We measure the branching fraction B(B-0 -> a(1)(+/-)(1260)pi(-/+))B(a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-))=(16.6 +/- 1.9 +/- 1.5)x10(-6), where the first error quoted is statistical and the second is systematic.

PhysicsAnnihilationMeson010308 nuclear & particles physicsBranching fractionElectron–positron annihilationAnalytical chemistryGeneral Physics and AstronomyResonance01 natural sciencesNuclear physics0103 physical sciencesPiB meson010306 general physicsPhysical Review Letters
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Measurements of the branching fractions of chargedBdecays toK±π∓π±final states

2004

We present results of searches for B-meson decays to K+ pi- pi+ with the BaBar detector. With a data sample of 61.6 million BBbar pairs, we measure the branching fractions and 90% confidence-level upper limits averaged over charge-conjugate states (the first error is statistical and the second is systematic): B+ --> K*0 pi+ = (15.5 +/- 1.8 +1.5 -4.0) x 10^-6, B+ --> f0 K+, f_0 --> pi+ pi- = (9.2 +/- 1.2 +2.1 -2.6) x 10^-6, B+ --> D0bar pi+, D0bar --> K+ pi- = (184.6 +/- 3.2 +/- 9.7) x 10^-6. B+ --> rho K+ K+ pi- pi+ non-resonant < 17 x 10^-6.

PhysicsNuclear and High Energy Physics010308 nuclear & particles physicsBranching fractionElectron–positron annihilationAnalytical chemistryDalitz plotBranching (polymer chemistry)Resonance (chemistry)01 natural sciencesParticle identificationNuclear physicsParticle decay0103 physical sciencesPi010306 general physicsPhysical Review D
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