Search for Exotic Strange Quark Matter in High Energy Nuclear Reactions

We report on a search for metastable positively and negatively charged states of strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864. We have sampled approximately six billion 10% most central Au+Pb interactions and have observed no strangelet states (baryon number A < 100 droplets of strange quark matter). We thus set upper limits on the production of these exotic states at the level of 1-6 x 10^{-8} per central collision. These limits are the best and most model independent for this colliding system. We discuss the implications of our results on strangelet production mechanisms, and also on the stability question of strange quark matter.Comment: 21 pages, 9 figures, to be published in Nuclear Physics A (Carl Dover memorial edition

Search for Strange Quark Matter Produced in Relativistic Heavy Ion Collisions

We present the final results from Experiment 864 of a search for charged and neutral strange quark matter produced in interactions of 11.5 GeV/c per nucleon Au beams with Pt or Pb targets. Searches were made for strange quark matter with A>4. Approximately 30 billion 10% most central collisions were sampled and no strangelet states with A<100 were observed. We find 90% confidence level upper limits of approximately 10^{-8} per central collision for both charged and neutral strangelets. These limits are for strangelets with proper lifetimes greater than 50 ns. Also limits for H^{0}-d and pineut production are given. The above limits are compared with the predictions of various models. The yields of light nuclei from coalescence are measured and a penalty factor for the addition of one nucleon to the coalescing nucleus is determined. This is useful in gauging the significance of our upper limits and also in planning future searches for strange quark matter.Comment: 35 pages, 18 figures, submitted to Phys. Rev.

Search for neutral strange quark matter in high energy heavy ion collisions

We present results of a search for neutral strange quark matter (strangelets) in 11.6A GeV/c Aut-Pb reactions from the 1995 run of experiment E864 at the Brookhaven Alternating Gradient Synchrotron. We have sampled approximately 1.3 billion 10% most central Au+Pb interactions and have observed no statistically significant signal for neutral strangelet states with baryon number in the range 620 GeV/c(2) These limits are the first limits reported on the production of heavy neutral strangelets. They complement searches for positively and negatively charged strangelets also conducted by our collaboration. We discuss the implications of these results on strangelet production mechanisms and the stability of strange quark matter. [S0556-2813(99)50504-9]

Search for charged strange quark matter produced in 11.5A GeV/c Au+Pb collisions

We present results of a search for strange quark matter (strangelets) in 11.5A GeV/c Au + Pb collisions from the 1994 and 1995 runs of experiment E864 at Brookhaven's Alternating Gradient Synchrotron. We observe no strangelet candidates and set a 90% confidence level upper limit of approximately 3 X 10(-8) per 10% central interaction for the production of \Z\ = 1 and \Z\ = 2 strangelets over a large mass range and with metastable lifetimes of about 50 ns or more. These results place constraints primarily on quark-gluon plasma based production models for strangelets. [S0031-9007(97)04465-7]

Search for exotic strange quark matter in high energy nuclear reactions

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The E864 lead-scintillating fiber hadronic calorimeter

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A spectrometer for study of high mass objects created in relativistic heavy ion reactions

Experiment E864 at the Brookhaven AGS accelerator uses a high sensitivity, large acceptance spectrometer, designed to search for strangelets and other novel forms of matter produced in high-energy heavy ion collisions. The spectrometer has excellent acceptance and rate capabilities for measuring the production properties of known particles and nuclei such as (p) over bar, (d) over bar and He-6. The experiment uses a magnetic spectrometer and employs redundant time of flight and position detectors and a hadronic calorimeter. In this paper we describe the design and performance of the spectrometer. (C) 1999 Elsevier Science B.V. All rights reserved