|
|||||
|
|
Scaling of charged particle multiplicity in Pb–Pb collisions at SPS energies |
|
| Institution: | a Università del Piemonte Orientale, Alessandria and INFN-Torino, Italy b LAPP, CNRS-IN2P3, Annecy-le-Vieux, France c LPC, Univ. Blaise Pascal and CNRS-IN2P3, Aubière, France d IFA, Bucharest, Romania e Università di Cagliari/INFN, Cagliari, Italy f CERN, Geneva, Switzerland g LIP, Lisbon, Portugal h INR, Moscow, Russia i IPN, Univ. de Paris-Sud and CNRS-IN2P3, Orsay, France j LPNHE, Ecole Polytechnique and CNRS-IN2P3, Palaiseau, France k Università di Torino/INFN, Torino, Italy l IPN, Univ. Claude Bernard and CNRS-IN2P3, Villeurbanne, France m YerPhI, Yerevan, Armenia |
| Abstract: | The charged particle multiplicity distribution dNch/dη has been measured by the NA50 experiment in Pb–Pb collisions at the CERN SPS. Measurements were done at incident energies of 40 and 158 GeV per nucleon over a broad impact parameter range. The multiplicity distributions are studied as a function of centrality using the number of participating nucleons (Npart), or the number of binary nucleon–nucleon collisions (Ncoll). Their values at midrapidity exhibit a power law scaling behaviour given by Npart1.00 and Ncoll0.75 at 158 GeV. Compatible results are found for the scaling behaviour at 40 GeV. The width of the dNch/dη distributions is larger at 158 than at 40 GeV/nucleon and decreases slightly with centrality at both energies. Our results are compared to similar studies performed by other experiments both at the CERN SPS and at RHIC. |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ | |