Recent studies on hypernuclei lifetimes from STAR

Abstract

The hyperon-nucleon (Y-N) interaction is an essential ingredient in the description of the equation-of-state of high-baryon-density matter. Light hypernuclei (A = 3, 4), being simple Y-N bound states, serve as cornerstones of our understanding of the Y-N interaction. Thus, precise measurements of their lifetimes are important, as they provide stringent tests to hyperon-nucleon interaction models. The yields of light hypernuclei are expected to increase from high to low energy heavy-ion collisions due to the increase in baryon density. As a result, the STAR Beam Energy Scan II program, which spans an energy range of √sNN = 3.0 − 27.0 GeV, is particularly suited for hypernuclei studies. In these proceedings, recent results on the lifetimes of light hypernuclei (3ΛH, 4ΛH, 4ΛHe) measured in √sNN = 3.0 and 7.2 GeV Au+Au collisions are presented. The relative branching ratio R3 of the 3ΛH is intimately related to its lifetime. A new R3 measurement using data from √sNN = 3.0 GeV Au+Au collisions is reported. These results will be compared to previous measurements and theoretical calculations, and the physics implications will be discussed.