Search results for "Parton shower"

showing 3 items of 33 documents

Properties of Hadronic Z-decays and Test of QCD Generators

1992

Distributions are presented of event shape variables, jet roduction rates and charged particle momenta obtained from 53 000 hadronic Z decays. They are compared to the predictions of the QCD + hadronization models JETSET, ARIADNE and HERWIG, and are used to optimize several model parameters. The JETSET and ARIADNE coherent parton shower (PS) models with running alpha(s) and string fragmentation yield the best description of the data. The HERWIG parton shower model with cluster fragmentation fits the data less well. The data are in better agreement with JETSET PS than with JETSET O(alpha(s)2) matrix elements (ME) even when the renormalization scale is optimized.

Quantum chromodynamicsPhysicsParticle physicsAlephPhysics and Astronomy (miscellaneous)Electron–positron annihilationPhysicsHadronHigh Energy Physics::PhenomenologyCharged particleHadronizationNuclear physicsRenormalizationHigh Energy Physics::ExperimentParton showerNuclear ExperimentEngineering (miscellaneous)Particle Physics - Experiment
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Determination of 55-155-155-1in second order QCD from hadronic Z decays

1992

Distributions of event shape variables obtained from 120600 hadronic Z decays measured with the DELPHI detector are compared to the predictions of QCD based event generators. Values of the strong coupling constant αs are derived as a function of the renormalization scale from a quantitative analysis of eight hadronic distributions. The final result, αs(MZ), is based on second order perturbation theory and uses two hadronization corrections, one computed with a parton shower model and the other with a QCD matrix element model. © 1992 Springer-Verlag.

Quantum chromodynamicsPhysicsParticle physicsPhysics and Astronomy (miscellaneous)010308 nuclear & particles physicsElectron–positron annihilationHadronHigh Energy Physics::Phenomenology01 natural sciencesHadronizationRenormalization0103 physical sciencesHigh Energy Physics::ExperimentPerturbation theory (quantum mechanics)010306 general physicsParton showerEngineering (miscellaneous)Event (particle physics)Zeitschrift für Physik C Particles and Fields
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Measurement of soft-drop jet observables in pp collisions with the ATLAS detector at s=13  TeV

2020

Jet substructure quantities are measured using jets groomed with the soft-drop grooming procedure in dijet events from 32.9  fb-1 of pp collisions collected with the ATLAS detector at s=13  TeV. These observables are sensitive to a wide range of QCD phenomena. Some observables, such as the jet mass and opening angle between the two subjets which pass the soft-drop condition, can be described by a high-order (resummed) series in the strong coupling constant αS. Other observables, such as the momentum sharing between the two subjets, are nearly independent of αS. These observables can be constructed using all interacting particles or using only charged particles reconstructed in the inner tra…

QuarkQuantum chromodynamicsPhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyObservable01 natural sciencesCharged particleGluonPseudorapidityPhase space0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsParton showerPhysical Review D
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