Formation and decay of an excited state in 11Li

Abstract

I address the formation and decay of an excited state in 11Li that may be the so-called soft dipole. I discuss why this soft dipole should be populated very weakly in two-proton removal from 13B. I have used a potential model to estimate its width for 2n cluster decay, which turns out to be well within the experimental limit. After correcting the data for efficiency, a simple Breit-Wigner curve, convoluted with the experimental resolution widths, is found to provide an excellent fit.