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

TL;DR

This study demonstrates the feasibility of hypernuclear spectroscopy using heavy-ion beams, successfully observing hypernuclear signals and measuring their lifetimes with significant statistical confidence.

Contribution

It introduces a novel experimental approach for hypernuclear spectroscopy with heavy-ion beams and provides initial measurements of hypernuclei lifetimes at 2 AGeV.

Findings

Detection of mbda, 3mbda H, and 4mbda H hypernuclei signals

Lifetimes measured as approximately 262 ps, 183 ps, and 140 ps

Significance levels of 6.7, 4.7, and 4.9 sigma

Abstract

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.