Evidence of strong dynamic core excitation in C 19 resonant break-up

Abstract

The resonant breakup of C19 on protons measured at RIKEN [Y. Satou, Phys. Lett. B 660, 320 (2008)PYLBAJ0370-269310.1016/j.physletb.2008.01.022] is analyzed in terms of a valence-core model for C19 that includes possible core excitations. The analysis of the angular distribution of a prominent peak appearing in the relative-energy spectrum could be well described with this model and is consistent with the previous assignment of 5/2+ for this state. Inclusion of core-excitation effects are found to be essential to giving the correct magnitude of the cross section for this state. By contrast, the calculation assuming an inert C18 core is found to largely underestimate the data.