J.B. Costales

Centrality dependence of kaon yields in Si + A and Au + Au collisions at the AGS

Charged kaon production has been measured in Si+Al and Si+Au collisions at 14.6 A GeV/c, and Au+Au collisions at 11.1 A GeV/c by Experiments 859 and 866 (the E--802 Collaboration) at the BNL AGS. Invariant transverse mass spectra and rapidity distributions for both K+ and K- are presented. The centrality dependence of rapidity-integrated kaon yields is studied. Strangeness enhancement is observed as an increase in the slope of the kaon yield with the total number of participants as well as the yield per participant. The enhancement starts with peripheral Si+Al and Si+Au collisions (relative to N+N) and appears to saturate for a moderate number of participating nucleons in Si+Au collisions. It is also observed to increase slowly with centrality in Au+Au collisions, to a level in the most central Au+Au collisions that is greater than that found in central Si+A collisions. The enhancement factor for

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

K^+

Production of phi mesons in central 28Si+196Au collisions at 14.6A GeV/c.

production are 3.0 +-0.2(stat.) +-0.4(syst.) and 4.0 +-0.3(stat.) +-0.5(syst.), respectively, for the most central 7% Si+Au collisions and the most central 4% Au+Au collisions relative to N+N at the correponding beam energy.

Intermittency in central collisions of 16O+A at 14.6A GeV/c☆

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

Particle production in pA and AA collisions at AGS

Production of the {phi} meson in central Si+Au collisions has been measured by E859 at the Brookhaven Alternating Gradient Synchrotron by selecting events with identified K{sup +}K{sup -} pairs. The mass and width of the {phi}, obtained from the invariant mass distribution of kaon pairs, are consistent with those of free f mesons. The transverse mass and rapidity distributions are presented. The inverse slope parameter for an exponential fit to the invariant transverse mass distribution is 179{+-}10{+-}17 MeV.

Production ofφMesons in CentralS28i+A196uCollisions at14.6AGeV/c

Abstract Fluctuations in pseudorapidity distributions of charged particles from central collisions of 16 O+Al and 16 O+Cu at 14.6 A GeV/ c are analyzed using scaled factorial moments. A power-law growth of moments with decreasing bin size is observed down to δη ∼ 0.1. About half the measured signal remains after making corrections based on Monte Carlo calculations with Fritiof and GEANT which include γ-conversions, Dalitz decays and detector effects.

The centrality dependence of the source size for Au - Au collisions at the AGS

Production of light particles (π±,K±,p) has been measured in both Si+A and p+A collisions. Several interesting features have been observed, among which are: the enhanced K+/π+ ratio and the larger 〈mt〉 for K+ and proton. Comparisons between ≊pp, pA and SiA collisions are discussed.

Recent results from E859 at the BNL AGS

Production of the {phi} meson in central Si+Au collisions has been measured by E859 at the Brookhaven Alternating Gradient Synchrotron by selecting events with identified K{sup +}K{sup -} pairs. The mass and width of the {phi}, obtained from the invariant mass distribution of kaon pairs, are consistent with those of free f mesons. The transverse mass and rapidity distributions are presented. The inverse slope parameter for an exponential fit to the invariant transverse mass distribution is 179{+-}10{+-}17 MeV.

Particle spectra near mid-rapidity studied with Cherenkov-complex system in 14.5 AGEV SI + AU collisions

Abstract Recent π − π − correlation measurements and deuteron to proton yield ratio measurements for AuAu collisions from Brookhaven E866 are presented. These measurements allow us, with some interpretation, to deduce the size of the participant region in a heavy ion collision. An unpredicted rise of the apparent source size is seen in the π − π − data at midrapidity. No corresponding drop in the deuteron to proton yield ratio is seen. Further experimental study is needed to improve the statistical significance of the correlation result and to determine whether it can be explained by conventional hadronic means.

Spectrometer results from BNL E802

Abstract This paper presents recent results from Experiment 859 at the BNL AGS, focussing on strangeness ( K ± , Λ, Λ ), rare probes ( p , φ) and two-particle correlations. Highlights of the paper include an analysis of the centrality dependence of K ± yields in terms of the number of participants, a brief review of the current status of the E859 Λ and Λ data, an analysis of the target dependence of p yields in terms of p K − ratios, results of a re-analysis of Λ feed-down contamination of p s, a comparison of the cenal SiAu and pp φ yields through the φ K − ratio, an extremely preliminary study of the centrality dependence of the φ line-shape, a summary of the centrality dependence of two-π correlation source sizes, and a comparison of results from two-dimensional analyses of the two-π and two-K + correlation functions.