Production of antimatter 5,6Li nuclei in central Au+Au collisions at sNN=200 GeV

Abstract

Combining the covariant coalescence model and a blast-wave-like analytical parametrization for (anti-)nucleon phase–space freezeout configuration, we explore light (anti-)nucleus production in central Au+Au collisions at sNN=200 GeV. Using the nucleon freezeout configuration (denoted by FO1) determined from the measured spectra of protons (p), deutrons (d) and 3He, we find the predicted yield of 4He is significantly smaller than the experimental data. We show this disagreement can be removed by using a nucleon freezeout configuration (denoted by FO2) in which the nucleons are assumed to freeze out earlier than those in FO1 to effectively consider the effect of large binding energy value of 4He. Assuming the binding energy effect also exists for the production of 5Li, Li‾5, 6Li and Li‾6 due to their similar binding energy values as 4He, we find the yields of these heavier (anti-)nuclei can be enhanced by a factor of about one order, implying that although the stable (anti-)6Li nucleus is unlikely to be observed, the unstable (anti-)5Li nucleus could be produced in observable abundance in Au+Au collisions at sNN=200 GeV where it may be identified through the p–4He (p‾–He‾4) invariant mass spectrum. The future experimental measurement on (anti-)5Li would be very useful to understand the production mechanism of heavier antimatter.