Kinematic identification of the βt branch in the decay of ~(11)Li

摘要

The β-delayed 8Li + t branch of the ~(11)Li decay was identified via kinematical analysis of the charged particles observed in coincidence. The back-to-back events observed in a narrow angular acceptance were compared to a Monte Carlo simulation. The ~(8)Li + t sum energy spectrum was fitted assuming that the decay occurs through an intermediate state in 11Be. The resulting energy centroid and full-width half maximum for the intermediate state are 18.35(30)MeV and 1.5(4)MeV, respectively. The β-delayed 8Li + t branching ratio obtained from the coincidence spectrum, BRt = 0.93(8) × 10-4, is in agreement with previous measurements but more precise.