Jet and underlying event properties as a function of particle multiplicity in proton-proton collisions at sqrt(s) = 7 TeV - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Journal Articles European Physical Journal C: Particles and Fields Year : 2013

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

S. Chatrchyan
  • Function : Author
P. Busson
R. Granier de Cassagnac
C. Mironov
P. Paganini
J.-L. Agram
C. Collard
E. Conte
P. van Hove
D. Contardo
M. Gouzevitch
M. Lethuillier
V. Sordini
P. Verdier
S. Viret

Abstract

Characteristics of multi-particle production in proton-proton collisions at sqrt(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 abs(eta) < 2.4 and transverse momentum pt > 0.25 GeV. Jets are reconstructed from charged-particles only and required to have pt > 5 GeV. The distributions of jet pt, average pt 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 pt 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.

Dates and versions

in2p3-00874498 , version 1 (18-10-2013)

Identifiers

Cite

S. Chatrchyan, M. Besançon, F. Couderc, M. Dejardin, D. Denegri, et al.. Jet and underlying event properties as a function of particle multiplicity in proton-proton collisions at sqrt(s) = 7 TeV. European Physical Journal C: Particles and Fields, 2013, 73, pp.2674. ⟨10.1140/epjc/s10052-013-2674-5⟩. ⟨in2p3-00874498⟩
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