Measurement of the centrality dependence of the charged-particle pseudorapidity distribution in proton-lead collisions at √{s_{_ {NN}}} = 5.02 TeV with the ATLAS detector
Abstract
The centrality dependence of the mean charged-particle multiplicity as a function of pseudorapidity is measured in approximately 1 μ b^{-1} of proton-lead collisions at a nucleon-nucleon centre-of-mass energy of √{s_{_ {NN}}} = 5.02 {TeV} using the ATLAS detector at the Large Hadron Collider. Charged particles with absolute pseudorapidity less than 2.7 are reconstructed using the ATLAS pixel detector. The [InlineEquation not available: see fulltext.] collision centrality is characterised by the total transverse energy measured in the Pb-going direction of the forward calorimeter. The charged-particle pseudorapidity distributions are found to vary strongly with centrality, with an increasing asymmetry between the proton-going and Pb-going directions as the collisions become more central. Three different estimations of the number of nucleons participating in the [InlineEquation not available: see fulltext.] collision have been carried out using the Glauber model as well as two Glauber-Gribov inspired extensions to the Glauber model. Charged-particle multiplicities per participant pair are found to vary differently for these three models, highlighting the importance of including colour fluctuations in nucleon-nucleon collisions in the modelling of the initial state of [InlineEquation not available: see fulltext.] collisions.
- Publication:
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European Physical Journal C
- Pub Date:
- April 2016
- DOI:
- 10.1140/epjc/s10052-016-4002-3
- arXiv:
- arXiv:1508.00848
- Bibcode:
- 2016EPJC...76..199A
- Keywords:
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- High Energy Physics - Experiment;
- Nuclear Experiment
- E-Print:
- 28 pages plus author list + cover pages (46 pages total), 14 figures, 4 tables, submitted to EPJC, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2012-15/