Charged particle multiplicity distributions in oxygen - nucleus collisions at 60 GeV and 200 GeV per nucleon

Multiplicity distributions of charged particles produced in the pseudorapidity range 0.9 < ηlab < 5.5 were measured in oxygen-nucleus collisions for Al, Ag, and W target nuclei at incident energies of 60 and 200 GeV per nucleon. The multiplicity differential cross sections and the pseudorapidity distributions as a function of transverse energy are presented for the various target nuclei. The correlation between charged multiplicity and transverse energy is studied as a function of transverse energy. Data are compared with predictions of the IRIS and FRITIOF generators

Measurement of the transverse energy flow in nucleus-nucleus collisions at 200 GeV per nucleon

The transverse energy distributions have been measured for interactions of 32S nuclei with Al, Ag, W, Pt, Pb, and U targets, at an incident energy of 200 GeV per nucleon in the pseudorapidity region −0.1 < νlab < 5.5. These distributions are compared with those for 16OW interactions in the same pseudorapidity region and with earlier measurements performed with 16O and 32S projectiles in the region −0.1 < νlab < 2.9. These comparisons provide both a better understanding of the dynamics involved and improved estimates of stopping power and energy density

Low-mass lepton-pair production in p-Be collisions at 450 GeV/c

We report on the production of low-mass electron pairs and muon pairs in p-Be collisions at 450 GeV/c at the CERN SPS. For both electron and muon pairs the low-mass spectrum can be explained satisfactorily by lepton pairs from hadronic decays, and there is no need to invoke any ''unconventional'' source. The normalisation of the major hadronic sources is set by the data. The upper limit, at 90% confidence level, on any new source of lepton pairs is similar to 20% of the hadronic decay contribution for muons, and similar to 40% for electrons

Inclusive negative particle pT spectra in p-nucleus and nucleus-nucleus collisions at 200-GeV per nucleon

The HELIOS experiment has measured inclusivep ⊥ spectra of negative particles in the rapidity region 1.0 is found to be approximately constant up to the highest accessible values of E ⊥

LOW-MASS LEPTON-PAIR PRODUCTION IN P-BE COLLISIONS AT 450 GEV/C

We report on the production of low-mass electron pairs and muon pairs in p-Be collisions at 450 GeV/c at the CERN SPS. For both electron and muon pairs the low-mass spectrum can be explained satisfactorily by lepton pairs from hadronic decays, and there is no need to invoke any ''unconventional'' source. The normalisation of the major hadronic sources is set by the data. The upper limit, at 90% confidence level, on any new source of lepton pairs is similar to 20% of the hadronic decay contribution for muons, and similar to 40% for electrons

Kaon production in 200-GeV/nucleon nucleus-nucleus collisions

Results from the HELIOS External Spectrometer on kaon production in 200 GeV/A S+W and p+W collisions are presented. The K/pi ratios are compared with results from a lower beam energy and are found to be remarkably similar. Evidence for secondary production of K+ by meson-baryon rescattering is reviewed. Our results at y = 1.0-1.5 are compared with neutral particle results at midrapidity