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Proton and deuteron production has been observed in S+S and S+Pb collisions at 200 A $\cdot$GeV and in Pb+Pb reactions at 158 A $\cdot$GeV at the CERN SPS accelerator. For Pb+Pb triton production was also measured. The p and d spectra as well as the p and t spectra were observed in similar rapidity ranges and over similar ranges of transverse momenta per nucleon, making it possible to interpret the cross sections of the composite particles in terms of coalescence mechanisms. Volumes of homogeneity were extracted and compared to pion-pair HBT interferometry results. Special attention is given to the dependence on transverse mass, centrality and rapidity. [ABSTRACT FROM AUTHOR]

Two-particle correlations of negative pions as a function of charged particle multiplicity are studied in Pb+Pb collisions at $\sqrt{s}=17.3$GeV per nucleon using the NA44 experiment at the CERN Super Proton Synchrotron(SPS). We find that the source size parameters increase with the charged particle multiplicity. However the slope of the source size parameters plotted as a function of charged multiplicity is slightly larger at high multiplicity than at low multiplicity. The value of $\lambda$ is independent of charged multiplicity. For Pb+Pb collisions, $R_L$ is larger than $R_{TS}$ and $R_{TO}$ for all multiplicity intervals, whereas these three radius parameters were approximately equal in S+Nucleus collisions. The ratios ( $R_L/R_{TS}$) and ( $R_L/R_{TO}$) for Pb+Pb data show almost no dependence on charged multiplicity. The duration of pion emission $\Delta \tau$ is constant at 3.8 $\pm$1.1 fm/ c as a function of the charged multiplicity in Pb+Pb collisions. Effective volume (V) is also calculated as V= $\pi\times R_{TS}^2\times R_L$, assuming a cylindrically shaped source. We found, within the limited statistics, the effective volume rapidly increases at high multiplicity. [ABSTRACT FROM AUTHOR]

Results of a pion interferometry analysis are presented for the reactions S+C, S+S, S+Cu, S+Ag, S+Au and O+Au at 200 GeV per nucleon. Correlation functions were measured for pairs of negative pions in narrow windows of transverse momentum and rapidity, as a function of the three components of the momentum difference vector in cylindrical coordinates. The measured two-pion correlation functions suggest a space-time evolution of the system which proceeds in the following way for central nucleus-nucleus collisions. After interpenetration of the incident nuclei, the pion source expands in a boost invariant way along the collision axis. Estimates for the proper time interval between the onset of expansion and pion decoupling, as well as for the duration of pion emission are ∼ 4 fm/c and <2 fm/c, respectively. The k dependence observed for R is consistent with the effect of resonance decays, alone or combined with slow transverse expansion. A linear dependence of the decoupling volume on the multiplicity is observed and indicates pion decoupling at a constant particle density. Presently available model predictions are briefly discussed [ABSTRACT FROM AUTHOR]

Multiplicities and spectra of strange particles ( $$\Lambda ,\bar \Lambda ,K_S^0 ,K^ +$$ and K produced in centralS+S,S+Ag andS+Au collisions at 200 GeV per nucleon are presented and compared with data on strange particle production in protonnucleus and nucleon-nucleon interactions. It is shown that strangeness production inS+Ag collisions is enhanced by a factor of two, similar to that found previously in centralS+S collisions. [ABSTRACT FROM AUTHOR]

The intermittency phenomenon is investigated in proton-gold, oxygen-gold, sulphur-gold and sulphur-sulphur collisions at 200 GeV per nucleon. The data were taken with the NA 35 streamer chamber detector at the CERN SPS. The data samples are carefully corrected for double counting of tracks and for contamination from photon conversions, particle decays and secondary interactions. The analysis is carried out in terms of factorial moments, using a new definition, and of correlation integrals. Both methods show the presence of nonstatistical fluctuations ('intermittency'). The main conclusions are: The observation of the effect for pairs of hadrons with negative charges and its near absence for pairs of opposite charges is consistent with the assumption that Bose-Einstein correlations yield the dominant contribution. The 'intermittency' effect is not proportional to (d n/d y) which would be expected in superposition models. The measured relation between the second and third factorial moment for negative hadrons indicates that genuine 3-particle correlations are small. The predictions of a Monte Carlo simulation which is based on the Lund Fritiof model with the inclusion of Bose-Einstein correlations agree with the experimental results. [ABSTRACT FROM AUTHOR]

Production of charged kaons in proton-sulphur, proton-gold, sulphur-sulphur and oxygen-gold collisions at 200 GeV/nucleon has been studied in the NA35 Streamer Chamber experiment. Rapidity and transverse mass distributions as well as mean multiplicities were obtained. The results are compared with nucleon-nucleon data and with model predictions. [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]

We present recent results on single particle transverse momentum distributions of pions, kaons and protons, measured in CERN Experiment NA44, of 200 AGeV/c S+S and 158 AGeV/c Pb+Pb central collisions. By comparing these data with thermal and transport models, freeze-out parameters like the temperature T and the chemical potentials ( μ , μ ) are extracted and discussed. [ABSTRACT FROM AUTHOR]