Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead-lead collisions at √s NN=2.76 TeV with the ATLAS detector
The ATLAS experiment at the LHC has measured the centrality dependence of charged particle pseudorapidity distributions over |η|<2 in lead-lead collisions at a nucleon-nucleon centre-of-mass energy of √s NN=2.76 TeV. In order to include particles with transverse momentum as low as 30 MeV, the data were recorded with the central solenoid magnet off. Charged particles were reconstructed with two algorithms (2-point "tracklets" and full tracks) using information from the pixel detector only. The lead-lead collision centrality was characterized by the total transverse energy in the forward calorimeter in the range 3.2<|η|<4.9. Measurements are presented of the per-event charged particle pseudorapidity distribution, dN ch/dη, and the average charged particle multiplicity in the pseudorapidity interval |η|<0.5 in several intervals of collision centrality. The results are compared to previous mid-rapidity measurements at the LHC and RHIC. The variation of the mid-rapidity charged particle yield per colliding nucleon pair with the number of participants is consistent with lower sNN results. The shape of the dN ch/dη distribution is found to be independent of centrality within the systematic uncertainties of the measurement. © 2012 CERN.
Aad, G; Abbott, B; Abdallah, J; Abdelalim, AA; Abdesselam, A; Abdinov, O; Abi, B; Abolins, M; Abramowicz, H; Abreu, H; Acerbi, E; Acharya, BS; Adams, DL; Addy, TN; Adelman, J; Aderholz, M; Adomeit, S; Adragna, P; Adye, T; Aefsky, S; Aguilar-Saavedra, JA; Aharrouche, M; Ahlen, SP; Ahles, F; Ahmad, A; Ahsan, M; Aielli, G; Akdogan, T; Åkesson, TPA; Akimoto, G; Akimov, AV; Akiyama, A; Alam, MS; Alam, MA; Albert, J; Albrand, S; Aleksa, M; Aleksandrov, IN; Alessandria, F; Alexa, C; Alexander, G; Alexandre, G; Alexopoulos, T; Alhroob, M; Aliev, M; Alimonti, G; Alison, J; Aliyev, M; Allport, PP; Allwood-Spiers, SE; Almond, J; Aloisio, A; Alon, R; Alonso, A; Alviggi, MG; Amako, K; Amaral, P; Amelung, C; Ammosov, VV; Amorim, A; Amorós, G; Amram, N; Anastopoulos, C; Andari, N; Andeen, T; Anders, CF; Anderson, KJ; Andreazza, A; Andrei, V; Andrieux, ML; Anduaga, XS; Angerami, A; Anghinolfi, F; Anjos, N; Annovi, A; Antonaki, A; Antonelli, M; Antonov, A; Antos, J; Anulli, F; Aoun, S; Aperio Bella, L; Apolle, R; Arabidze, G; Aracena, I; Arai, Y; Arce, ATH; Archambault, JP; Arfaoui, S; Arguin, JF; Arik, E; Arik, M; Armbruster, AJ; Arnaez, O; Arnault, C; Artamonov, A; Artoni, G; Arutinov, D; Asai, S; Asfandiyarov, R
Volume / Issue
Start / End Page
International Standard Serial Number (ISSN)
Digital Object Identifier (DOI)