Population of low-seniority isomeric states of Hg206 by two-proton knockout reactions at relativistic energies

We consider calculations of direct two-proton removal reactions from a relativistic-energy Pb208 beam incident on a Be9 target, leading to the population of two-proton-hole isomeric configurations in Hg206. The calculated 5- and 10+ isomeric state population ratios of 18.8% and 4.7%, respectively, are in fair agreement with the values deduced experimentally (21.9-2.9+1.2% and 3.1-1.2+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 γ-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.