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

We consider calculations of direct two-proton removal reactions from a relativistic-energy {sup 208}Pb beam incident on a {sup 9}Be target, leading to the population of two-proton-hole isomeric configurations in {sup 206}Hg. The calculated 5{sup -} and 10{sup +} isomeric state population ratios of 18.8% and 4.7%, respectively, are in fair agreement with the values deduced experimentally (21.9{sub -2.9}{sup +1.2}% and 3.1{sub -1.2}{sup +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 {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.