G. Vesztergombi

Multiplicity and transverse energy flux in 16O+Pb at 200 GeV per nucleon

Abstract First results from ultrarelativistic 16 O+Pb collisions at 200 GeV/nucleon are presented. The transverse energy E T in average central collisions is ≈ 75 GeV for the interval 2.2⩽ y ⩽3.8. A 16-fold convolution of the inelastic p+Au transverse energy spectrum, also measured at 200 GeV, reproduces the mean E T of 16 O+Pb. The amount of nuclear stopping power appears to be high.

Neutral strange particle production in sulphur-sulphur and proton-sulphur collisions at 200 GeV/nucleon

AbstractThe production of Λ,

Negative particle production in nuclear collisions at 60 and 200 GeV/nucleon

\bar \Lambda

Pion and proton spectra in 32S + S collisions at 200 GeV/nucleon

andKs0 has been studied in 200 GeV/nucleonp+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 top+p andp+S collisions. The latter collisions show no overall (relative) strangeness enhancement overp+p, but the rapidity distributions and hadron multiplicities indicate some secondary cascading production of Λ particles in thep+S andp+Au collisions. The Λ polarization in central S+S collisions was found to be compatible with zero up topT=2 GeV/c.

Study of the energy flow in16O-nucleus collisions at 60 and 200 GeV/nucleon

Abstract We report results from a pion interferometry analysis of 200 GeV/nucleon 16 O+Au collisions. Both a gaussian source model and a model based on the inside-outside cascade are used to fit the experimental correlation function, giving transverse and longitudinal shape parameters, a freeze-out time parameter, and a chaoticity parameter for the pion emitting source. We find a transverse source size consistent with the projectile radius except at the CM rapidity, where significantly larger transverse and longitudinal sizes and a longer freeze-out time are measured suggesting a thermalized source. Calculation of correlation lengths, and comparisons with a simple freeze-out model and other pion interferometry experiments are presented.

Study of the energy flow in sulphur-and oxygen-nucleus collisions at 60 and 200 GeV/nucleon

The results on spectra of negative particles produced in16O+Au andp-Au collisions at 200 GeV/nucleon and16O+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 central16O+Au andp-Au collisions. The transverse momentum and rapidity distributions for central16O+Au andp-Au collisions differ strongly from corresponding distributions forp+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.

Charged particle multiplicities in nuclear collisions at 200 GeV/N

Results from a pion interferometric analysis of the system 200 GeV/nucleon16O+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

PION INTERFEROMETRY IN ULTRARELATIVISTIC NUCLEAR COLLISIONS

Abstract Rapidity spectra of pions and participant protons in S + S collisions at 200 GeV/nucleon are compared with N + N data. The average energy loss of the participating nucleons increases by 23% and is balanced by the energy of the final state particles, through a twofold increase of strange particle production and a similar enhancement, assumed for baryon-antibaryon pairs.