Physics of strange matter

With the advent of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), Heavy Ion Physics will enter a new energy regime. The question is whether the signatures proposed for the discovery of a phase transition from hadronic matter to a Quark Gluon Plasma (QGP), that were established on the basis of collisions at the BEVALAC, the AGS, and the SPS, respectively, are still useful and detectable at these high incident energies. In the past two decades, measurements related to strangeness formation in the collision were advocated as potential signatures and were tested in numerous fixed target experiments at the AGS and the SPS. In this article I will review the capabilities of the RHIC detectors to measure various aspects of strangeness, and I will try to answer the question whether the information content of those measurements is comparable to the one at lower energies.

Section: Strange Quark Mattermentioning

confidence: 99%

Is strangeness still interesting at RHIC?

Bellwied

1999

“…However, even QGP formation has not been indisputably observed [10]. That strangelets may be distilled is even more speculative [11].…”

Section: Introductionmentioning

confidence: 99%

Negatively charged strangelet search using the E864 spectrometer at the AGS

Buren

1999

We provide a status report on the progress of searching for negatively charged strangelets using the E864 spectrometer at the AGS. About 200 million recorded events representing approximately 14 billion 10% central interactions of Au + Pt at 11.5 GeV/c taken during the 1996-1997 run of the experiment are used in the analysis. No strangelet candidates are seen for charges Z = −1 and Z = −2, corresponding to a 90% confidence level for upper limits of strangelet production of ∼1 × 10 −8 and ∼4 × 10 −9 per central collision respectively. The limits are nearly uniform over a wide range of masses and are valid only for strangelets which are stable or have lifetimes greater than ∼50 ns.

“…The QGP distillation scenario assumes that strangelet formation is a two-step process: the creation of QGP followed by QGP decay into strangelet. These two processes are in the speculative stage [11]. Some estimations are available in [8,13] in which the QGP is assumed to break up into small droplets before distillation.…”

Section: Introductionmentioning

confidence: 99%

Search for positively charged strangelets and other related results with E864 at the AGS

1999

We report on the latest results in the search for positively charged strangelets from E864's 96/97 run at the AGS with sensitivity of about 8 × 10 −9 per central collision. This contribution also contains new results of a search for highly charged strangelets with Z = +3. Production of light nuclei, such as 6 He and 6 Li, is presented as well. Measurements of yields of these rarely produced isotopes near midrapidity will help constrain the production levels of strangelets via coalescence. E864 also measures antiproton production which includes decays from antihyperons. Comparisons with antiproton yields measured by E878 as a function of centrality indicate a large antihyperon-to-antiproton ratio in central collisions.