Population of low-seniority isomeric states ofHg206by two-proton knockout reactions at relativistic energies

Abstract

We consider calculations of direct two-proton removal reactions from a relativistic-energy $^{208}\mathrm{Pb}$ beam incident on a $^{9}\mathrm{Be}$ target, leading to the population of two-proton-hole isomeric configurations in $^{206}\mathrm{Hg}$. The calculated ${5}^{\ensuremath{-}}$ and ${10}^{+}$ isomeric state population ratios of $18.8%$ and $4.7%$, respectively, are in fair agreement with the values deduced experimentally (${21.9}_{\ensuremath{-}2.9}^{+1.2}%$ and ${3.1}_{\ensuremath{-}1.2}^{+1.0}%$); however, the high density of final states in this case complicates the prediction of isomeric ratios for those states fed by unobserved prompt $\ensuremath{\gamma}$-ray cascades. We also consider and quantify the effects of selection of events, according to the longitudinal momenta of the reaction residues, on the measured isomeric ratios for high-spin final states and, hence, of the potential to exploit such sensitivity to gain further insight into the reaction mechanism.