Structure of isobaric analog states in 91Nb populated by the 90Zr(a,t)   reaction
  Decay via proton emission of isobaric analog states (IAS's) in $^{91}{Nb}$ was studied using the $^{90}{Zr}(\alpha,t)$ reaction at $E_\alpha$=180 MeV. This study provides information about the damping mechanism of these states. Decay to the ground state and low-lying phonon states in $^{90}{Zr}$ was observed. The experimental data are compared with theoretical predictions wherein the IAS `single-particle' proton escape widths are calculated in a continuum RPA approach. The branching ratios for decay to the phonon states are explained using a simple model. 
H.K.T. van der Molen, H. Akimune, A.M. van den Berg, I. Daito, H.   Fujimura, Y. Fujita, M. Fujiwara, M.N. Harakeh, F. Ihara...