W. A. Zajc

A search for glueballs and a study of doouble pomeron exchange at the CERN intersecting storage rings

We present results from a study of centrally produced mesons in 3 × 106 events with two small-angle protons at the CERN Intersecting Storage Rings. A high-statistics sample of exclusive pp → ppπ+π− events at √s = 63 GeV has been obtained, where the reaction mechanism is dominated by double pomeron exchange. Scalar or tensor glueballs may be produced by this process. The π+π− mass spectrum has a distinctive structure, and analysis shows that the data are dominantly S-wave up to 1600 MeV. The behaviour of the D-wave provides evidence for a 2++ resonance (M = 1480 ± 50 MeV, Γ = 150 ± 50 MeV) in addition to the f(1270). We also show data on exclusive K+K−, pp, and π+π−π+π− production, and on the analogous reaction αα → ααπ+π− at √s = 126 GeV. Flavour independence is suggested by the observation of approximately equal numbers of K+K− and π+π− pairs for mass above 1 GeV. The mass spectra are also apparently independent of √s (45, 63, 126 GeV) and incident particle type (p, α).

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.

Bose-Einstein correlations for Levy stable source distributions

Abstract.The peak of the two-particle Bose-Einstein correlation functions has a very interesting structure. It is often believed to have a multivariate Gaussian form. We show here that for the class of stable distributions, characterized by the index of stability

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

0 < \alpha \le 2

Bose-Einstein correlations in αα, pp and pp interactions

, the peak has a stretched exponential shape. The Gaussian form corresponds then to the special case of

The Fluid Nature of Quark-Gluon Plasma

\alpha = 2

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

. We give examples for the Bose-Einstein correlation functions for univariate as well as multivariate stable distributions, and we check the model against two-particle correlation data.

The dominance of jets at large transverse energy in a full-azimuth hadron calorimeter at ISR energies

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

A study of exclusive central hadron production at the ISR as a search for gluonium states

K^+

Pion interferometry in jet events at the CERN Intersecting Storage Rings

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.