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

Apresyan, A. and Bornheim, A. and Bunn, J. and Chen, Y. and Gataullin, M. and Ma, Y. and Mott, A. and Newman , H. B. and Rogan, C. and Shin, K. and Timciuc, V. and Traczyk, P. and Veverka, J. and Wilkinson, R. and Yang, Y. and Zhu, R. Y. and Dubinin, M. and Spiropulu, M. (2011) Measurement of the underlying event activity at the LHC with √s = 7 TeV and comparison with √s = 0.9 TeV. Journal of High Energy Physics, 2011 (9). p. 109. ISSN 1126-6708. http://resolver.caltech.edu/CaltechAUTHORS:20111222-115337167

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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 √s = 0.9 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η|<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 signicant 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 trackjet, 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.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1007/JHEP09(2011)109DOIUNSPECIFIED
http://www.springerlink.com/content/w23340l25l806231/PublisherUNSPECIFIED
Additional Information:© 2011 CERN, for the benefit of the CMS collaboration. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Received: July 1, 2011; accepted: August 31, 2011; published: September 23, 2011. We thank Mark Strikman (Penn State University) and Torbjorn Sjöstrand (Lund University) for useful discussions and for assistance in simulating theoretical models. We wish to congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC machine. We thank the technical and administrative staff at CERN and other CMS institutes, and acknowledge support from:FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MSI (New Zealand); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie programme and the European Research Council (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Associazione per lo Sviluppo Scientico e Tecnologico del Piemonte (Italy); the Belgian Federal Science Policy Offce; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); and the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium).
Group:CMS@Caltech
Funders:
Funding AgencyGrant Number
FMSR (Austria)UNSPECIFIED
FNRS and FWO (Belgium) UNSPECIFIED
CNPq (Brazil)UNSPECIFIED
CAPES (Brazil)UNSPECIFIED
FAPERJ (Brazil)UNSPECIFIED
FAPESP (Brazil)UNSPECIFIED
MES (Bulgaria)UNSPECIFIED
CERNUNSPECIFIED
CAS (China)UNSPECIFIED
MoST (China)UNSPECIFIED
NSFC (China)UNSPECIFIED
COLCIENCIAS (Colombia)UNSPECIFIED
MSES (Croatia)UNSPECIFIED
RPF (Cyprus) UNSPECIFIED
Academy of Sciences and NICPB (Estonia) UNSPECIFIED
Academy of FinlandUNSPECIFIED
MEC (Finland)UNSPECIFIED
HIP (Finland)UNSPECIFIED
CEA (France)UNSPECIFIED
CNRS/IN2P3 (France)UNSPECIFIED
BMBF (Germany)UNSPECIFIED
DFG (Germany)UNSPECIFIED
HGF (Germany)UNSPECIFIED
GSRT (Greece)UNSPECIFIED
OTKA and NKTH (Hungary) UNSPECIFIED
DAE and DST (India) UNSPECIFIED
IPM (Iran)UNSPECIFIED
SFI (Ireland)UNSPECIFIED
INFN (Italy)UNSPECIFIED
WCU (Korea) UNSPECIFIED
LAS (Lithuania)UNSPECIFIED
CINVESTAV (Mexico)UNSPECIFIED
CONACyT (Mexico)UNSPECIFIED
SEP (Mexico)UNSPECIFIED
UASLP-FAI (Mexico)UNSPECIFIED
MSI (New Zealand)UNSPECIFIED
PAEC (Pakistan)UNSPECIFIED
SCSR (Poland)UNSPECIFIED
FCT (Portugal)UNSPECIFIED
JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan)UNSPECIFIED
MST and MAE (Russia) UNSPECIFIED
MSTD (Serbia)UNSPECIFIED
MICINN and CPAN (Spain) UNSPECIFIED
Swiss Funding Agencies (Switzerland)UNSPECIFIED
NSC (Taipei)UNSPECIFIED
TUBITAK and TAEK (Turkey) UNSPECIFIED
STFC (United Kingdom)UNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
NSFUNSPECIFIED
Marie-Curie programmeUNSPECIFIED
European Research Council (European Union)UNSPECIFIED
Leventis FoundationUNSPECIFIED
A. P. Sloan FoundationUNSPECIFIED
Alexander von Humboldt FoundationUNSPECIFIED
Associazione per lo Sviluppo Scientico e Tecnologico del Piemonte (Italy)UNSPECIFIED
Belgian Federal Science Policy OfficeUNSPECIFIED
Fonds pour la Formation à la Recherche dans l’índustrie et dans l’Ágriculture (FRIA-Belgium)UNSPECIFIED
Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium)UNSPECIFIED
Subject Keywords:Hadron-Hadron Scattering
Record Number:CaltechAUTHORS:20111222-115337167
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20111222-115337167
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:28571
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:22 Dec 2011 23:18
Last Modified:17 Dec 2014 23:32

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