超氚核寿命之谜及其展望（英文）

Hypertriton Lifetime Puzzle and Its Perspective

近期,基于重离子碰撞的实验组(HypHI,STAR)发表了超氚核(hypertriton)的寿命测量结果。其结果显示,超氚核的寿命比Λ超子短~30%。由于超氚核是一个非常松散的结合态,超氚核的寿命不应远离Λ超子的寿命太多。这一难以解释的现象被称为超氚核的短寿命之谜。为了从不同的实验方法检验超氚核的寿命,我们提出利用J-PARC的K-束流,通过K^-+3He→Λ3H+π~0的反应道来测量超氚核寿命的实验。本文将回顾测量超氚核寿命的主要结果,并介绍目前实验方面的最新进展。本合作组提出的原创性实验方案不会受到径迹重建效率的影响,能够为验证超氚核的寿命提供重要的实验数据。

Recent heavy ion experiments(HypHI,STAR)announced surprisingly short lifetime forΛ3H mesonic weak decay(MWD),which is difficult to interpret given the fact thatΛ3H is a very loosely bound system.This intriguing issue is known as hypertriton lifetime puzzle.In order to test the lifetime of the hypertriton with different experimental methods,we propose to use the K-beam of J-PARC to measure the lifetime of the hypertriton through the reaction channel of K^-+-3He→Λ3H+π0.In this article,we will summarize the situation and introduce some recent activities aiming at solving this puzzle.Our method will not suffer from the track reconstruction efficiency as the heavy ion based experiments;thus provide an important test for the hypertriton lifetime puzzle with comparable precision.