0000000000368518

AUTHOR

Ralf Kaiser

showing 4 related works from this author

Transverse momentum distributions for exclusive $\varrho^{0}$ muoproduction

1992

We have studied transverse momentum distributions for exclusive rho(0) muoproduction on protons and heavier nuclei at 2 < Q2 < 25 GeV2. The Q2 dependence of the slopes of the p(t)2 and t' distributions is discussed. The influence of the non-exclusive background is investigated. The p(t)2-slope for exclusive events is 4.3 +/- 0.6 +/- 0.7 GeV-2 at large Q2. The p(t)2 spectra are much softer than inclusive p(t)2 spectra of leading hadrons produced in deep inelastic scattering.

forward spectrometer: experimental resultsPhysics and Astronomy (miscellaneous)Nuclear Theorymuon nucleus: nuclear reactionchemistry.chemical_elementElementary particlemuon deuteron: nuclear reaction530Nuclear physicsmass spectrum: two-pionmomentum transfer: slopespectrum: transverse momentumField theory (psychology)Quantum field theoryNuclear Experimentrho(770)0: electroproductionEngineering (miscellaneous)muon p: exclusive reactionPhysicspomeron: exchangecalciumtwo-pion: mass spectrumbackgroundelectroproduction: rho(770)0carbon200 GeVCERN SPSDeep inelastic scatteringParticle accelerationexchange: pomeronchemistrytransverse momentum: spectrumQuantum electrodynamicsTransverse momentumHigh Energy Physics::ExperimentCarbonParticle Physics - Experimentmuon p --> rho(770)0 nucleon
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Nuclear-mass dependence of azimuthal beam-helicity and beam-charge asymmetries in deeply virtual Compton scattering

2009

The nuclear-mass dependence of azimuthal cross section asymmetries with respect to charge and longitudinal polarization of the lepton beam is studiedfor hard exclusive electroproduction of real photons. The observed beam-charge and beam-helicity asymmetries are attributed to the interference between the Bethe-Heitler and deeply virtual Compton scattering processes. For various nuclei, the asymmetries are extracted for both coherent and incoherent-enriched regions, which involve different (combinations of) generalized parton distributions. For both regions, the asymmetries are compared to those for a free proton, and no nuclear-mass dependence is found.

Nuclear and High Energy PhysicsParticle physicsPhotonNuclear TheoryHERAFOS: Physical sciencesIMPACT PARAMETER SPACEPartonGENERALIZED PARTON DISTRIBUTIONS; IMPACT PARAMETER SPACE; SPIN; HERA01 natural sciences7. Clean energyHigh Energy Physics - ExperimentNuclear physicsHigh Energy Physics - Experiment (hep-ex)GENERALIZED PARTON DISTRIBUTIONS0103 physical sciencesddc:530Nuclear Experiment010306 general physicsPhysicsElastic scattering010308 nuclear & particles physicsScatteringCompton scatteringHERASPINPhysics::Accelerator PhysicsHigh Energy Physics::ExperimentNucleonBeam (structure)
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The OLYMPUS Experiment

2014

Nuclear instruments &amp; methods in physics research / A 741, 1 - 17 (2014). doi:10.1016/j.nima.2013.12.035

two-photon [exchange]Physics - Instrumentation and DetectorsPhysics::Instrumentation and DetectorsHadronluminosity: monitoringRecoil4-MOMENTUM TRANSFERSNuclear Experiment (nucl-ex)Nuclear ExperimentInstrumentationNuclear ExperimentPhysicsElastic scatteringLuminosity (scattering theory)ELECTROMAGNETIC FORM-FACTORSInstrumentation and Detectors (physics.ins-det)elastic scattering [cross section]positron p: elastic scatteringAntimatterdrift chamberelastic scattering [electron p]target [hydrogen]proportional chamberCROSS-SECTIONNuclear and High Energy PhysicsELECTRON-PROTONDESY DORIS StorFOS: Physical sciencesmonitoring [luminosity]time-of-flight530electron p: elastic scatteringNuclear physicsCross section (physics)RATIO(GEV/C)(2)p: form factor: ratiocalorimeterddc:530cross section: elastic scatteringactivity reporthydrogen: targetexchange: two-photonScatteringPOSITRONSDESYelastic scattering [positron p]magnetic spectrometerELECTROMAGNETIC FORM-FACTORS; PROTON ELASTIC-SCATTERING; 4-MOMENTUM TRANSFERS; ELECTRON-PROTON; CROSS-SECTION; RATIO; (GEV/C)(2); POSITRONSform factor: ratio [p]gas electron multiplierPhysics::Accelerator PhysicsPROTON ELASTIC-SCATTERINGHigh Energy Physics::Experiment
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Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering Determined by the OLYMPUS Experiment

2017

The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, $R_{2\gamma}$, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of $\approx 20\degree$ to $80\degree$. The relative luminosity between the two beam species was mo…

ratioPhysics::Instrumentation and DetectorsHadronFOS: Physical sciencesSocio-culturaleGeneral Physics and AstronomyElectron01 natural sciencestransfersNuclear physicsEconomica0103 physical sciencesddc:550electromagnetic form factorsNuclear Experiment (nucl-ex)010306 general physicselectromagnetic form factors transfers ratioNuclear ExperimentPhysicsLuminosity (scattering theory)010308 nuclear & particles physicsScatteringGenerator (category theory)Form factor (quantum field theory)BremsstrahlungHigh Energy Physics::ExperimentLeptonPhysical Review Letters
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