Search

We report the first measurements of cumulants, up to 4 t h order, of deuteron number distributions and proton-deuteron correlations in Au+Au collisions recorded by the STAR experiment in phase-I of Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider. Deuteron cumulants, their ratios, and proton-deuteron mixed cumulants are presented for different collision centralities covering a range of center-of-mass energy per nucleon pair s NN = 7.7 to 200 GeV. It is found that the cumulant ratios at lower collision energies favor a canonical ensemble over a grand canonical ensemble in thermal models. An anti-correlation between proton and deuteron multiplicity is observed across all collision energies and centralities, consistent with the expectation from global baryon number conservation. The UrQMD model coupled with a phase-space coalescence mechanism qualitatively reproduces the collision-energy dependence of cumulant ratios and proton-deuteron correlations. [ABSTRACT FROM AUTHOR]

Abstract: A track based maximum likelihood algorithm, unbiased to any mass hypothesis, has been developed for the HERA-B RICH to search for deuterons produced in 920GeV proton–nucleus collisions. Clear signals of deuterons and anti-deuterons have been observed in data recorded by the HERA-B spectrometer. We present the algorithm, discuss its performance and show some preliminary results of an ongoing data analysis. [Copyright &y& Elsevier]