A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at root s = 0.9 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity vertical bar eta vertical bar < 2 and transverse momentum p(T) > 0.5 GeV = c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-p(T) sum of the particles in the transverse region is observed with increasing p(T) of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet p(T) larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in PYTHIA are compared to the data.

Measurement of the underlying event activity at the LHC with root s=7 TeV and comparison with root s=0.9 TeV

AMAPANE, Nicola Carlo;ARGIRO', Stefano;BOTTA, CRISTINA;CASTELLO, Roberto;COSTA, Marco;MIGLIORE, Ernesto;MONACO, Vincenzo;MUSICH, MARCO;OBERTINO, Maria Margherita;PELLICCIONI, Mario;ROMERO, Alessandra;SACCHI, Roberto;SOLA, VALENTINA;SOLANO, Ada Maria;BELLAN, Riccardo;COVARELLI, Roberto;
2011-01-01

Abstract

A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at root s = 0.9 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity vertical bar eta vertical bar < 2 and transverse momentum p(T) > 0.5 GeV = c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-p(T) sum of the particles in the transverse region is observed with increasing p(T) of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet p(T) larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in PYTHIA are compared to the data.
2011
09
109
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Hadron-Hadron Scattering
S. Chatrchyan;V. Khachatryan;A. M. Sirunyan;A. Tumasyan;W. Adam;T. Bergauer;M. Dragicevic;J. Eroe;C. Fabjan;M. Friedl;R. Fruehwirth;V. M. ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/96519
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