Level scheme study of Mo92 : Searching for evidence of core excitation

Abstract

Excited states in $^{92}\mathrm{Mo}$ are populated via the $^{89}\mathrm{Y}(^{6}\mathrm{Li},\phantom{\rule{0.16em}{0ex}}3n)^{92}\mathrm{Mo}$ reaction at the tandem of XTU, INFN-LNL. The level scheme of $^{92}\mathrm{Mo}$ is revised and expanded considerably by the $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ coincidence measurement. The newly observed level structures are compared with different shell-model calculations performed in various model spaces. The results show that the several high-energy ($\ensuremath{\approx}2$ MeV) transitions, observed for the first time in the current work, could be a presumable signature of $N=50$ core-breaking effect. The measured strengths of $E1$ transitions between the low-lying positive and negative bands indicate an important contribution from $Z=28$ proton core-excitation.