Characteristics of multi-particle production in proton-proton collisions at root s = 7 TeV are studied as a function of the charged-particle multiplicity, N (ch). The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |eta|< 2.4 and transverse momentum p (T)> 0.25 GeV/c. Jets are reconstructed from charged-particles only and required to have p (T)> 5 GeV/c. The distributions of jet p (T), average p (T) of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of N (ch) and compared to the predictions of the pythia and herwig event generators. Predictions without multi-parton interactions fail completely to describe the N (ch)-dependence observed in the data. For increasing N (ch), pythia systematically predicts higher jet rates and harder p (T) spectra than seen in the data, whereas herwig shows the opposite trends. At the highest multiplicity, the data-model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients.

Jet and underlying event properties as a function of charged-particle multiplicity in proton-proton collisions at root s=7 TeV / Chatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., Eroe, J., Fabjan, C., Friedl, M., Fruehwirth, R., Ghete, V.M., Hoermann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knuenz, V., Krammer, M., Kraetschmer, I., Liko, D., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - ELETTRONICO. - 73:2674:(2013), pp. 1-26. [10.1140/epjc/s10052-013-2674-5]

Jet and underlying event properties as a function of charged-particle multiplicity in proton-proton collisions at root s=7 TeV

CIULLI, VITALIANO;D'ALESSANDRO, RAFFAELLO;FOCARDI, ETTORE;FROSALI, SIMONE;GONZI, SANDRO;GORI, VALENTINA;LENZI, PIERGIULIO;TROPIANO, ANTONIO;
2013

Abstract

Characteristics of multi-particle production in proton-proton collisions at root s = 7 TeV are studied as a function of the charged-particle multiplicity, N (ch). The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |eta|< 2.4 and transverse momentum p (T)> 0.25 GeV/c. Jets are reconstructed from charged-particles only and required to have p (T)> 5 GeV/c. The distributions of jet p (T), average p (T) of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of N (ch) and compared to the predictions of the pythia and herwig event generators. Predictions without multi-parton interactions fail completely to describe the N (ch)-dependence observed in the data. For increasing N (ch), pythia systematically predicts higher jet rates and harder p (T) spectra than seen in the data, whereas herwig shows the opposite trends. At the highest multiplicity, the data-model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients.
2013
73:2674
1
26
Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Eroe, J.; Fabjan, C.; Friedl, M.; Fruehwirth, ...espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/862512
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