Observation of Enhanced Monopole Strength and Clustering in 12Be
发表刊物： Physical Review Letters
摘要： In a recent breakup-reaction experiment using a 12Be beam at 29 MeV/nucleon, the 0+ band head of the expected 4He+8He molecular rotation was clearly identified at about 10.3 MeV, from which a large monopole matrix element of 7.0±1.0 fm2 and a large cluster-decay width were determined for the first time. These findings support the picture of strong clustering in 12Be, which has been a subject of intense investigations over the past decade. The results were obtained thanks to a specially arranged detection system around zero degrees, which is essential in determining the newly emphasized monopole strengths to signal the cluster formation in a nucleus.