Transverse-Momentum and Pseudorapidity Distributions of Charged Hadrons in pp Collisions at √s=7 TeV

Authors

• V. Khachatryan, Yerevan Physics Institute
• Kenneth A. Bloom, University of Nebraska - LincolnFollow
• S. Bose, University of Nebraska - LincolnFollow
• J. Butt, University of Nebraska - Lincoln
• Daniel R. Claes, University of Nebraska - LincolnFollow
• Aaron Dominguez, University of Nebraska-LincolnFollow
• Michael Eads, University of Nebraska - LincolnFollow
• J. Keller, University of Nebraska - LincolnFollow
• T. Kelly, University of Nebraska - Lincoln
• Ilya Kravchenko, University of Nebraska-LincolnFollow
• J. Lazo-Flores, University of Nebraska - LincolnFollow
• Carl Lundstedt, University of Nebraska - LincolnFollow
• H. Malbouisson, University of Nebraska - Lincoln
• Sudhir Malik, University of Nebraska - LincolnFollow
• Gregory Snow, University of Nebraska - LincolnFollow
• CMS Collaboration, CMS Collaboration

Document Type

Article

Date of this Version

2010

Comments

Published in Physical Review Letters 105, 022002 (2010). DOI: 10.1103/PhysRevLett.105.022002. Copyright 2010 CERN, forCMS Collaboration.

Abstract

Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at √s=7 TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN_ch=dη ⃒_|η|<0.5= 5.78 ± 0.01(stat) ± 0.23(syst) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from √s=0.9 to 7 TeV is [±66.1 ± 1.0(stat) ± 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 ± 0.005(stat) ± 0.015(syst) GeV/c. The results are compared with similar measurements at lower energies.