Search

Multiplicity distributions of charged particles produced in proton-proton, proton-argon and proton-xenon inelastic collisions at 200 GeV/c in various rapidity intervals are presented. Nuclear target data are analysed separately for the forward and the backward hemispheres. Results of a similar analysis for only negative particles are shown. The data are well parametrized in terms of negative binomial distributions. However, such a parametrization fails in describing the p-nucleus multiplicity distributions of charged particles for large rapidity intervals comprising both hemispheres. Parameters characteristic for the clan model of Giovannini and Van Hove are also presented. [ABSTRACT FROM AUTHOR]

Multiplicity distributions of negatively charged particles have been studied in restricted phase space intervals for central S+S, O+Au and S+Au collisions at 200 GeV/nucleon. It is shown that multiplicity distributions are well described by a negative binomial form irrespectively of the size and dimensionality of phase space domain. A clan structure analysis reveals interesting similarities between complex nuclear collisions and a simple partonic shower. The lognormal distribution agrees reasonably well with the multiplicity data in large domains, but fails in the case of small intervals. No universal scaling function was found to describe the shape of multiplicity distributions in phase space intervals of varying size. [ABSTRACT FROM AUTHOR]

Multiplicity distributions and their second moments fornegatively charged particles produced inS-S central and minimum bias interactions at 200 A GeV are studied in various rapidity intervals. Fritiof and Venus models mostly describe the dependence of second moments on rapidity intervals in minimum bias interactions, but not in central collisions. For central collisions the behaviour of second moments might indicate enhanced multiplicity fluctuations. [ABSTRACT FROM AUTHOR]

We report on a systematic study of midrapidity transverse energy production and forward energy flow in interactions ofO andS projectiles with S, Cu, Ag and Au targets at 60 and 200 GeV/nucleon. The variation of the shape of the E distributions with target and projectile mass can be understood from collision geometry. Average E values determined for central collisions show an increasing stopping power for heavier target nuclei. A higher relative stopping is observed at 60 GeV/nucleon than at 200 GeV/nucleon. Bjorken estimates of the energy density reach approximately 3 GeV/fm in high E events at 200 GeV/nucleon withO andS projectiles. The systematics of the data and the shapes of E and pseudorapidity distributions are well described by the Lund model Fritiof. [ABSTRACT FROM AUTHOR]

Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed. [ABSTRACT FROM AUTHOR]

The production of Λ, $$\bar \Lambda$$ and K has been studied in 200 GeV/nucleon p+S and S+S collisions in the streamer chamber of the NA35 experiment at the CERN SPS. Significant enhancement of the multiplicities of all observed strange particles relative to negative hadrons was observed in central S+S collisions, as compared to p+p and p+S collisions. The latter collisions show no overall (relative) strangeness enhancement over p+p, but the rapidity distributions and hadron multiplicities indicate some secondary cascading production of Λ particles in the p+S and p+Au collisions. The Λ polarization in central S+S collisions was found to be compatible with zero up to p=2 GeV/c. [ABSTRACT FROM AUTHOR]

The production of neutral strange particles K , Λ and $$\bar \Lambda $$ has been studied in 60 and 200 GeV per nucleon OAu and pAu collisions with the streamer chamber vertex spectrometer of the NA35 experiment at the CERN-SPS accelerator. Ratios of neutral strange particle production to negatively charged particle production in selected regions of phase space were measured to be the same in OAu and pAu reactions. The rates of strange particle production in central OAu collisions are about a factor of 16 higher than in pAu collisions when compared in the same regions of phase space. If an enhancement of strange particle production in OAu collisions relative to pAu collisions is considered to be a signature for quark-gluon plasma formation, no evidence supporting it is observed. The experimental results are compared to the Lund FRITIOF model. [ABSTRACT FROM AUTHOR]

We report a systematic study of mid-rapidity E production and forward energy flow in the interaction ofO projectiles on Al, Cu, Ag and Au at 60 and 200 GeV/nucleon. First results on E production withS projectiles are presented. [ABSTRACT FROM AUTHOR]

Results from a pion interferometric analysis of the system 200 GeV/nucleonO+Au, central collisions, are reported. Both a Gaussian source model and a model based on the inside-outside cascade are used to fit to the experimental correlation function, giving transverse and longitudinal shape parameters, a freezeout time parameter, and a chaoticity parameter for the pion emitting source. We find a transverse [ABSTRACT FROM AUTHOR]

The results on spectra of negative particles produced inO+Au and p-Au collisions at 200 GeV/nucleon andO+Au at 60 GeV/nucleon are presented. The correlations of average rapidity and average transverse momentum with event multiplicity are studied. Spectral shapes are similar for centralO+Au and p-Au collisions. The transverse momentum and rapidity distributions for centralO+Au and p-Au collisions differ strongly from corresponding distributions for p+ p interactions. The FRITIOF model fails to describe the shapes of the transverse momentum distributions. The simple thermodynamical model of a single fireball does not fit the midrapidity transverse momentum distributions, and the rapidity distributions. [ABSTRACT FROM AUTHOR]

We present the first preliminary results on Λ, K and $$\bar \Lambda$$ production on a gold target with proton and oxygen beams in the NA35 streamer chamber. [ABSTRACT FROM AUTHOR]

An analysis of correlations in rapidity of charged particles produced in proton and antiproton interactions on hydrogen, argon and xenon at 200 GeV is presented. Positive long-range correlations are observed in interactions on heavy targets. The dependence of rapidity correlations between the forward and backward hemisphere on the number of projectile collisions is discussed. [ABSTRACT FROM AUTHOR]