Recent Progress in Antimatter Research with Heavy-Ion Collisions

Matter–antimatter asymmetry is a fundamental question in both astronomy and particle physics. Investigating antimatter is of great interest for testing the potential explanations of matter–antimatter asymmetry in our Universe. In relativistic heavy-ion collisions, the extremely high energy density and temperature are similar to the early Universe shortly after the Big Bang. In this paper, we review the recent progress in antimatter search and study heavy-ion collisions, with a focus on the RHIC-STAR and LHC-ALICE experiments, particularly the newly observed antimatter hypernuclei H¯Λ¯4 and He¯Λ¯4. The statistical thermal model and the coalescence production model can quantitatively describe the production yields and yield ratios, and the yield measurements of H¯Λ¯4, He¯Λ¯4 and their matter counterparts indicate the existence of spin-excited states of these (anti)hypernuclei. Furthermore, new measurements of the lifetimes of H¯Λ¯3, H¯Λ¯4 and their matter counterparts reveal no difference between a particle and its corresponding antiparticle, which validates the CPT theorem.