Search results for "PACS: 13.20.Gd"

showing 3 items of 3 documents

Search for Production of Invisible Final States in Single-Photon Decays of Υ(1S)

2010

We search for single-photon decays of the Upsilon(1S) resonance, Upsilon->gamma+invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A0, or a pair of dark matter particles, chi chi-bar. Both A0 and chi are assumed to have zero spin. We tag Upsilon(1S) decays with a dipion transition Upsilon(2S)->pi+pi-Upsilon(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m_A0<=9.2 GeV and m_chi<=4.5 GeV in the sample of 98e6 Upsilon(2S) decays collected with the BaBar detector and set stringent limits on new physics models that contain light dark ma…

Particle physicsPhotonAstrophysics::High Energy Astrophysical PhenomenaPhysics beyond the Standard ModelElectron–positron annihilationDark matterFOS: Physical sciencesGeneral Physics and Astronomy01 natural sciencesResonance (particle physics)High Energy Physics - ExperimentNuclear physicsHigh Energy Physics - Experiment (hep-ex)PACS: 13.20.Gd 12.60.Jv 14.80.Da 95.35.+d0103 physical sciencessingle-photon decays of Upsilon(1S)[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]010306 general physicsLight dark matterPhysicsMissing energy010308 nuclear & particles physicsParticle physicsBABAR detectorHEPBaBarHiggs bosonHigh Energy Physics::ExperimentFísica de partículesExperimentsBaBar detector at SLAC
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Study of radiative bottomonium transitions using converted photons

2011

We use 111+/-1 million Upsilon(3S) and 89+/-1 million Upsilon(2S) events recorded by the BaBar detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions between bottomonium states using photons that have been converted to e+e- pairs by the detector material. We observe Upsilon(3S) -> gamma chi_b0,2(1P) decay, make precise measurements of the branching fractions for chi_b1,2(1P,2P) -> gamma Upsilon(1S) and chi_b1,2(2P) -> gamma Upsilon(2S) decays, and search for radiative decay to the eta_b(1S) and eta_b(2S) states.

Nuclear and High Energy PhysicsParticle physicsMesonElectron–positron annihilationHadronbottomoniumFOS: Physical sciences01 natural sciencesHigh Energy Physics - ExperimentNuclear physicsHigh Energy Physics - Experiment (hep-ex)Particle decayBaBar detector at SLAC; radiative bottomonium transitions0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Radiative transfer010306 general physicsPACS: 13.20.Gd 14.40.PqPhysics010308 nuclear & particles physicsBranching fractionParticle physicsQuarkoniumHEPconverted photons3. Good healthbottomonium; converted photonsPair productionradiative bottomonium transitionsBaBarBaBar detector at SLACFísica de partículesExperimentsPhysical Review D
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Search for charged lepton flavor violation in narrow Y decays

2010

Charged-lepton flavor-violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models with leptoquarks or compositeness. We present a search for such processes in a sample of 99 × 10 6 Υ ( 2 S ) decays and 117 × 10 6 Υ ( 3 S ) decays collected with the BABAR detector. We place upper limits on the branching fractions B ( Υ ( n S ) → e ± τ ∓ ) and B ( Υ ( n S ) → μ ± τ ∓ ) ( n = 2 , 3 ) at the 10 − 6 level and use these results to place lower limits of order 1 TeV on the mass scale of charged-lepton flavor-violating effective operators.

Particle physicsPACS: 13.20.Gd 11.30.Hv 14.40.NdPhysics beyond the Standard ModelBABARGeneral Physics and AstronomyElementary particle01 natural sciencesPARTICLE PHYSICS; PEP2; BABARParticle identificationParticle decay0103 physical sciencesPEP2Grand Unified Theory010306 general physicsPhysics010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologySupersymmetryBABAR detectorHEPPARTICLE PHYSICSHigh Energy Physics::ExperimentFísica de partículesExperimentsLepton
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