The pseudorapidity density of charged particles, dNch=dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of sNN 1⁄4 5.02 TeV. For the 5% most central collisions, we measure a value of 1943 +/- 54. The rise in dNch=dη as a function of sNN is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dNch=dη as a function of the average number of participant nucleons, hNparti, calculated in a Glauber model, is compared with the previous measurement at sNN 1⁄4 2.76 TeV. A constant factor of about 1.2 describes the increase in dNch=dη from sNN 1⁄4 2.76 to 5.02 TeV for all centrality classes, within the measured range of 0%–80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.

Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at √sNN = 5.02 TeV

CAMERINI, Paolo;FRAGIACOMO, ENRICO;LEA, RAMONA;LUPARELLO, GRAZIA;MARGAGLIOTTI, GIACOMO;PIANO, STEFANO;RUI, RINALDO;ŠULJIĆ, MILJENKO;Zaccolo, V.;
2016

Abstract

The pseudorapidity density of charged particles, dNch=dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of sNN 1⁄4 5.02 TeV. For the 5% most central collisions, we measure a value of 1943 +/- 54. The rise in dNch=dη as a function of sNN is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dNch=dη as a function of the average number of participant nucleons, hNparti, calculated in a Glauber model, is compared with the previous measurement at sNN 1⁄4 2.76 TeV. A constant factor of about 1.2 describes the increase in dNch=dη from sNN 1⁄4 2.76 to 5.02 TeV for all centrality classes, within the measured range of 0%–80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.222302
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2879981
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