0000000000423344

AUTHOR

D. Stoker

showing 2 related works from this author

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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Subjet multiplicity of gluon and quark jets reconstructed with thek⊥algorithm inpp¯collisions

2002

The D empty set Collaboration has studied for the first time the properties of hadron-collider jets reconstructed with a successive-combination algorithm based on relative transverse momenta (k(perpendicular to)) of energy clusters. Using the standard value D = 1.0 of the jet-separation parameter in the k(perpendicular to) algorithm, we find that the p(T) of such jets is higher than the E-T of matched jets reconstructed with cones of radius R = 0.7, by about 5 (8) GeV at p(T) approximate to90 (240) GeV. To examine internal jet structure, the k(perpendicular to) algorithm is applied within D = 0.5 jets to resolve any subjets. The multiplicity of subjets in jet samples at roots = 1800 GeV and…

QuarkPhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsAstrophysics::High Energy Astrophysical PhenomenaMultiplicity (mathematics)RadiusJet (particle physics)Deep inelastic scattering01 natural sciencesGluonNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentResummationNuclear Experiment010306 general physicsAlgorithmEvent generatorPhysical Review D
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