M. Kramer

Λ production by 11.6 A GeV/c Au beam on Au target

Abstract We present the first measurement at AGS energies of the rapidity and transverse mass distributions for Λ production with Au beam on Au target. The measurements cover the rapidity region of 2.0–3.2 and transverse momenta of 0.0–1.4 GeV/c. The results are compared with the predictions of two models.

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).

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.

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.

H0 candidates from the decay H0 → Σ−p, observed in heavy ion collisions with 14.6 × A GeV/c Si beam on Pb target

Abstract We present H 0 candidate events, where the H 0 is observed through the decay H 0 → Σ − p . These decays are reconstructed in the three TPC modules of E810 while triggering on central Si Pb events at 14.6 × A GeV/c Si beam.

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.

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.

Recent results from E-810

Abstract I discuss data from E-810 including K 0 and Λ production, the rise in production of negative particles at small m ⊥ , and the rapidity distributions. The data are compared to various models; in particular they do not agree with a model indicating large nuclear transparency.

Searching for quark-gluon plasma (QGP) bubble effects at RHIC/LHC

Since the early eighties, we have shared with Leon Van Hove the following view. That if a QGP were produced in high energy heavy ion colliders, that its hadronization products would likely come from small localized in phase space bubbles of plasma. We develop a model based on HIJING, to which we added a ring of adjoining multiple bubbles in the central rapidity region. Our simulations were designed to be tested by the forthcoming RHIC STAR detector data for 65 GeV/n Au colliding with 65 GeV/n Au. We took into account background and resonance effects to allow a direct comparison with the data. Later 100 GeV/n Au colliding with 100 GeV/n Au and LHC data could also test these ideas. We used two charged particle correlations as a sensitive method to test for bubbles.