Hypernuclear spectroscopy of products from 6Li projectiles on a carbon target at 2 AGeV

Understand

A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy-ion beams, was conducted.

• Using the invariant mass method, the spectroscopy of hypernuclear products of 6Li projectiles on a carbon target at 2 AGeV was performed.
• Signals of the \Lambda-hyperon and 3\Lambda H and 4\Lambda H hypernuclei were observed for final states of p+\pi^-, 3He+\pi^- and 4He+\pi^-, respectively, with significance values of 6.7, 4.7 and 4.9\sigma.
• By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be $262 ^{+56}_{-43} \pm 45$ ps for \Lambda, $183 ^{+42}_{-32} \pm 37$ ps for 3\Lambda H, and $140 ^{+48}_{-33}\pm 35 $ ps for 4\Lambda H.