P. Vincent

A Single arm spectrometer detector system for high-energy heavy ion experiments

The recent availability of 14.6 GeV/c per nucleon 16O and 28Si ions from the Brookhaven National Laboratory Tandem-AGS accelerator facility has prompted the design, construction and operation of a large-solid-angle (25 msr) magnetic spectrometer with particle identification from ∼0.5 to ∼4.7 GeV/c. A small-solid-angle Cherenkov counter complex views the target through the magnet and extends the particle identification up to ∼15 GeV/c. This experiment (E-802) employs event characterization detectors, a charged-particle multiplicity array, a highly segmented lead-glass detector, and a zero degree calorimeter. The facility measures momentum spectra of identified heavy-ion-produced hadrons with high resolution (Δp/p≤0.005) as a function of collision centrality given by triggers from the event characterization detectors. Construction and performance details of the spectrometer components and auxiliary detectors are described.

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

Results from the BNL E802 spectrometer for 14.5 GeV/c per nucleon silicon beams

We present selected results of measurements of inclusive ..pi.., K, proton, and deuteron spectra from 14.5 A GeV/c Si collisions with various targets. Results of neutral energy and charged particle dN/d/eta/ measurements are also discussed. Large K to ..pi.. ratios are observed in Si + Au collisions. Results are compared to the Lund-Fritiof model. 11 refs., 11 figs.

Recent results from E802 and E859

Abstract Recent single-particle inclusive measurements and two-particle correlation data from E802 and its succesor, E859, are presented. The K + / π + ratio observed for collisions of 14.6 A·GeV 28 Si ions on various targets is presented as a function of both forward and transverse energy. Source sizes are determined via interferometry using π + , π − , K + and proton pairs.

Antiproton production in 14.6 AGeVc Si+A collisions

Abstract Antiproton production cross sections have been measured for minimum bias and central Si+Al and Si+Au collisions at 14.6 A GeV c . The data presented cover the range of transverse momentum from 0.3 to 1.2 GeV c and lab rapidities from 1.1 to 1.7 units. The relative p π − and p K − yields are found to be the smallest for the heaviest system measured, central Si+Au collisions. For these collisions, the p π − ratio, determined from integrated yields for 1.1⩽y⩽1.7, is (0.84±0.07)×10−3. In the same rapidity interval, the average antiproton inverse m⊥ slope is 141±14 MeV for central Si+Al and central Si+Au collisions.

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.

Centrality dependence of K+ and π+ multiplicities from Si + A collisions at 14.6 A GeV/c☆

Abstract K + and π + multiplicities have been measured in magnetic spectrometer for Si++ Al, Si+ Cu and Si + Au collisions at 14.6 A GeV/ c incident momentum. The multiplicities were obtained for five different windows of forward kinetic energy as detected in a zero degree calorimeter. The K + / π + multiplicity ratio ranges from ≈9% in peripheral interactions to 19% in central Si+Au. The largest K + / π + ratios are observed for those events for each target that leave the least energy in the zero degree calorimeter and the ratio increases with target mass. The observations suggest that multiple interactions are important in the particle production mechanism.

The E802 aerogel Cherenkov detector

Abstract A highly segmented aerogel Cherenkov detector has been designed and constructed for use in measurements of inclusive and semi-exclusive particle production in 15 GeV/c per nucleon nucleus-nucleus collisions. The counter consists of 96 separate cells of refractive index n = 1.02 aerogel. A diffusion box is utilized to transport the Cherenkov light to 5 in. phototubes. Light yields in excess of 8 photoelectrons have been obtained.

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

Bose-Einstein correlations in 14.6 A · GeV/c 28Si + A collisions

Abstract The E802 spectrometer at the Brookhaven AGS has been used to obtain two-particle inclusive pion distributions from E / A = 14.6 GeV 28 Si + 197 Au arid 27 A1 interactions. Data are presented for pions near center-of-mass rapidity, in the nucleon-nucleon frame, from central events. We present preliminary results for source distribution parameters obtained by fitting the two-particle correlation function. The potential for studying kaon correlations in the E802 apparatus is also discussed.