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

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 2AGeV was performed. Signals of the Λ-hyperon and HΛ3 and HΛ4 hypernuclei were observed for final states of 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±45ps for Λ, 183−32+42±37ps for HΛ3, and 140−33+48±35ps for HΛ4.