Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead-lead collisions at root s(NN)=2.76 TeV with the ATLAS detector

Journal Article · Thu Apr 12 04:00:00 EDT 2012 · Physics Letters, (Section) B

OSTI ID:1043418

Aad, G; Abbott, B; Abdallah, J; A, Abdelalim A; Abdesselam, A; Abdinov, O; Abi, B; Abolins, M; Abramowicz, H; Abreu, H; Acerbi, E; S, Acharya B; L, Adams D; N, Addy T; Adelman, J; Aderholz, M; Adomeit, S; Adragna, P; Adye, T

The ATLAS experiment at the LHC has measured the centrality dependence of charged particle pseudorapidity distributions over |{eta}| < 2 in lead-lead collisions at a nucleon-nucleon centre-of-mass energy of {radical}s{sub 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 < |{eta}| < 4.9. Measurements are presented of the per-event charged particle pseudorapidity distribution, dN{sub ch}/d{eta}, and the average charged particle multiplicity in the pseudorapidity interval |{eta}| < 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 {radical}s{sub NN} results. The shape of the dN{sub ch}/d{eta} distribution is found to be independent of centrality within the systematic uncertainties of the measurement.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1043418
• Report Number(s): BNL--98090-2012-JA; KA1101021
• Journal Information: Physics Letters, (Section) B, Journal Name: Physics Letters, (Section) B Journal Issue: 3 Vol. 710; ISSN PYLBAJ; ISSN 0370-2693
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGORITHMS
CALORIMETERS
CHARGED PARTICLES
DISTRIBUTION
MAGNETS
MULTIPLICITY
NUCLEONS
SHAPE
SOLENOIDS
TRANSVERSE ENERGY
TRANSVERSE MOMENTUM