D. Greiner

The STAR time projection chamber: a unique tool for studying high multiplicity events at RHIC

The STAR Time Projection Chamber (TPC) is used to record the collisions at the Relativistic Heavy Ion Collider (RHIC). The TPC is the central element in a suite of detectors that surrounds the interaction vertex. The TPC provides complete coverage around the beam-line, and provides complete tracking for charged particles within ± 1.8 units of pseudo-rapidity of the center-of-mass frame. Charged particles with momenta greater than

Measurement of energy emission from O+A and p+A collisions at 14.5 GeV/c per nucleon with a lead-glass array

Abstract The first data from a 16O beam of total energy 232 GeV at the BNL Tandem-AGS are reported. A lead-glass array covering the laboratory pseudo-rapidity interval 1.25

Strangeness production at mid-rapidity in S + Pb collisions at 200 GeV/c per nucleon

Abstract Experimental evidence is presented for a source of unusually high strangeness content located at mid-rapidity in 200 GeV/ c per nucleon collisions of 32 S projectiles with a Pb target. The enhancement is not seen in p+Pb reactions measured in the same apparatus at the same energy. This source becomes dominant for central collisions.

Multiplicity dependence of strangeness production in S + Pb collisions at 200 GeV/c per nucleon

Abstract Production of Λ, Λ , and K s 0 has been measured for a wide range of event multiplicity in S+Pb reactions at 200 GeV/c per nucleon. The production of Λ is shown to increase with multiplicity faster than expected from a superposition of p+p collisions. The effect is seen for low multiplicity (below 100 negative particles).

Measurement of energy and charged particle emission in the central rapidity region from O+A and p+A collisions at 14.5 GeV/c per nucleon and preliminary results from Si+A collisions

The first data from a16O beam of total energy 232 GeV at the BNL Tandem-AGS are discussed. Preliminary results from a28Si beam of total energy 406 GeV are also shown. The full complement of E802, including a magnetic spectrometer, was used for the28Si measurement. A different experimental arrangement was used for16O. Comparison measurements with proton beams are presented for both configurations.

Production of Λ, Λ, and Ξ−, Ξ+ particles in S+Pb collisions at 200 GeV/c per nucleon☆

Abstract The yields of Λ, Λ , and Ξ−, Ξ + have been measured close to mid-rapidity in sulphur reactions on a Pb target at 200 GeV/c per nucleon beam momentum. Fully corrected production ratios of Λ Λ , Ξ + Ξ , Ξ − Λ and Ξ Λ are presented. The ratios have been analysed both in the context of a rapidly disintegrating quark-gluon plasma and a hadronic resonance gas. Our analysis shows that the hadron gas model is sufficient to explain the observed particle yields.

A measurement of cross sections for 16O Al and 16O Pb interactions at 60 and 200 GeV/c per nucleon

Abstract Cross sections are measured for 16 O collisions with A1 and Pb. Dependences on beam momentum and atomic number are compared with data obtained at much lower beam momenta.

A measurement of cross sections for 32S interactions with Al, Fe, Cu, Ag and Pb at 200 GeV/c per nucleon

Abstract Cross sections for charge changing and particle production are measured for 32 S collisions with Al, Fe, Cu, Ag and Pb targets at 200 GeV/ c . The measured difference between the two cross sections is discussed. Results are compared with data obtained with an 16 O beam.

Determination of the primary vertex position in the NA36 experiment

Abstract A new method is described for finding the primary vertex in a relativistic heavy-ion experiment with multiple nuclear targets. Due to the large number of tracks the use of an economic algorithm is essential. The method comes from system theory and is based on an application of the Kalman filter. The small uncertainty in the vertex position obtained provides a reliable target assignment for the interaction.

Results from the NA36 experiment on the production of strangeness vbS| = 1 and |S| = 2 particles

Abstract Measurements of the production of singly and doubly strange particles in S + Pb collisions at a beam momentum of 200 GeV c per nucleon are presented. The yield of singly strange particles as a function of negative particle multiplicity has been measured. Rapidity and transverse momentum distributions from events consistent with a maximum impact parameter of 9 fm are compared with the predictions of Fritiof 7.02, Venus 4.10 and RQMD 1.08. The comparison illustrates the importance of re-interactions of secondaries and suggests that additional physical processes are required to be incorporated into the event generators. The analysis of strange particle ratios indicates that strangeness phase space is not saturated in these collisions.