A simulation study of a silicon pixel multiplicity detector proposed for the NA57 experiment at CERN SPS has been carried out to evaluate its capability to measure both the total multiplicity and the ...net baryon content created in Pb+Pb collisions at 40 and 160 GeV/
c per nucleon in order to get information on the specific entropy produced in the reaction. A method of charge assignment is proposed and discussed in detail and the results of the simulation are presented. A benchmark of the method using computer-generated events is also performed.
The multiplicity of charged particles in the central rapidity region has been measured by the NA57 experiment in Pb–Pb collisions at the CERN SPS at two beam momenta: 158 A GeV/c and 40 A GeV/c. The ...value of dNch/dη at the maximum has been determined and studied as a function of centrality within the range covered by NA57 (about 55 most central part of the inelastic cross section). The central rapidity multiplicity varies roughly linearly with the number of wounded nucleons (participants) and increases approximately logarithmically with the centre of mass energy.
Charged particle pseudorapidity density distributions in Au induced reactions in nuclear emulsion at 10.7 A GeV have been measured. In peripheral events the shower particle distribution exhibits a ...two peak structure while in central collisions it has a Gaussian shape. The spectator protons appear in the second peak in the pseudorapidity spectra and exhibits a broader momentum distribution than expected from Fermi motion. The produced particle yield in central collisions is not substantially different from phenomenological descriptions based on data from O and S induced reactions.
Angular distributions of projectile-associated He fragments from Pb induced reactions on stationary Pb target at 158 A GeV/c incident momentum are reported. The precision of the angular measurements ...was about ±0.01 mrad. Two emission components are appearing in the projected angular spectra of the He particles, one representing fragmentation at Fermi momentum scale, while the other one exhibits large transverse momentum transfer. By scaling with the incident momentum the angular spectra of He particles are compared with earlier reported measurements of Au on Au interactions at 11.6 A GeV/c. The
p
T
spectrum of the He particles appears the same for the two cases.
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