A. C. Saulys

Observation of three 2++ resonances in the glueball-enhanced channel π-p → φφn☆

Abstract We present data on 3652 analyzed events of the reaction π - p → φφn at 22 GeV/ c . A partial wave analysis has been performed on the φφ system. The results are well represented by three resonances all with quantum numbers I G J PC = 0 + 2 ++ . The absence of the Okubo-Zweig-Iizuka suppression observed in this reaction, the selection of only three J PC =2 ++ states ( g T , g T′ , and g T ″ ) which comprise virtually all of the cross section, and the large φφn signal over a very different φK + K - n background are all well explained if these states are produced by 1–3 glueballs (i.e. multigluon resonances).

The MPS II drift chamber system

Abstract A description is given of a drift chamber system that has very good resolution and beam rate capabilities in a compact and reasonably priced package.

Rapidity distributions of Ks0's and Λ's produced by 14.6×A GeV/cSi beams on Si and Pb targets

Abstract We present the first measurement at AGS energies of rapidity distributions of K s 0 and Λ production with silicon beams on silicon and lead targets. The measurements cover the rapidity region of 2.0 y K s 0 s and 1.4 y Λ s.

Modular TPCs for relativistic heavy-ion experiments☆

Abstract A description is given of a TPC system that operates in a relativistic heavy-ion beam and yields good track reconstruction efficiency in very-high-multiplicity events. The mechanical construction of the chamber is discussed. A set of custom hybrid circuits are used to build a very compact, cost-effective electronics system mounted directly on the chamber. Results from running in test beams and from preliminary experimental runs are given.

Neutral V production with 14.6 ×A GeV/c silicon beams

Abstract We present the results of a measurement of neutral V production with 14.6 × A GeV/ c Si beams on Au and Cu targets. The Λ and K s 0 yields were measured as a function of negative particle multiplicity. Effective temperatures were determined from an exponential fit to the transverse mass distributions.

An update on the strangeness production measurements and H0 di-baryon search as performed by the AGS experiment 896

E896 was designed to search for the predicted short-lived six-quark H0 di-baryon. The goal is to enhance the existing knowledge by extending the search into regions of shorter lifetimes (approximately half that of the lambda) and via exploring a new creation channel, that of the coalescence of two lambdas. Two main tracking chambers are used, a distributed drift chamber positioned to measure low-pt and high-rapidity neutral particle decay products and a silicon drift detector array which measures particle production at mid-rapidity. Both detectors are also investigating lambda polarization, over their respective coverages, for Au-Au collisions at 11.3 GeV/nucleon. The current status of the H0 di-baryon search and preliminary results of the strange particle production and polarization measurements will be presented.

Rapidity distributions and nuclear transparency in heavy ion collisions

Abstract We have measured the rapidity distributions for charged particles produced in SiAu collisions at 14.6× A GeV/ c . No evidence is seen for enhanced production of protons at high rapidity as recently postulated based on fits to earlier data.

Transverse momentum distributions of π− from 14.6A GeV/c silicon ion interactions in copper and gold

Abstract A measurement of the transverse momentum spectrum of negatively charged tracks from AGS energy silicon ion collisions is presented. The spectrum has a different shape than that of nucleon-nucleon collisions at approximately the same energy. The transverse mass spectrum is well represented by a sum of two exponentials with different slopes and may be reasonably well accounted for by a model of pion production in interacting nuclear matter that includes resonance production and decay.

A TPC for large solid angle relativistic ion experiments

A TPC (time projection chamber) detector system has been developed to function in the very-high-multiplicity environment of relativistic-heavy-ion experiments. A TPC was chosen because it directly gives three-dimensional points on the tracks, which is a very significant help for track-finding. Of prime importance is a combination of high efficiency, low noise, and two track resolution capability. A significant development is a system of hybridized, high-sensitivity, on-chamber digitizing electronics. A description of the TPC modules, the digitizing electronics, and test results is given. >

Ξ− production in heavy ion collisions at the AGS☆

Abstract We report the first observation of Ξ − in heavy ion collisions at the AGS. The lifetime of Ξ − measured agrees very well with the particle data group value. We present the observed Ξ − effective mass spectrum and the rapidity distribution after acceptance correction. In the measured rapidity region (1.4−2.9) for 14.6 GeV/ c Si on Pb, we obtained a yield of 0.25 ± 0.04 Ξ − per central event and a ratio of N ( Ξ − )/ N ( Λ ) = 0.12 ± 0.02 using a fireball + model (a model which includes a fireball plus a term simulating a cascade) for acceptance correction (see text for systematic error). This result is larger than any cascade model prediction so far.