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

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 2A GeV was performed. Signals of the Λ  -hyperon and HΛ3 and HΛ4 hypernuclei were observed for final states of p+π−p+π−, He3+π− and He4+π−, respectively, with significance values of 6.7, 4.7 and 4.9σ  . By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be 262−43+56±45 ps for Λ  , 183−32+42±37 ps for HΛ3, and 140−33+48±35 ps for HΛ4.