中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

Hypernuclei are bound nuclear systems of non-strange and strange baryons, i.e. nucleons and hyperons. As such, hypernuclei are correlated hyperon-baryon systems and therefore provide direct access to study the hyperon$-$nucleon (Y-N) interaction. Production of hypernuclei in collider systems provides an experimental avenue for studying the Y-N interaction. $\Lambda$ hypernuclei, such as $^3_{\Lambda}H$ and $^4_{\Lambda}H$, are usually understood as a weakly bound system of a $\Lambda$ and a nucleus. According to this concept, the $\Lambda$ maintains its identity even if embedded in a system of other nucleons. Since the lifetime of a hypernucleus depends on the strength of the Y-N interaction, precise lifetime measurements of hypernuclei help us to understand the Y-N interaction. In this talk, we will present the first lifetime measurements of $^3_{\Lambda}H$ and $^4_{\Lambda}H$ in Au+Au Collisions at $\sqrt{s_{NN}}$ = 7.2 GeV, recorded by the STAR experiment with a fixed target mode in the year 2018.