Gamma decays of isobaric analog states relevant to neutrino detection

Measurements have been made of the gamma ray branching ratios for the decay of the lowest isobaric analog states of Ge71 and Kr81. These states could be populated by high-energy neutrinos in gallium- and bromine-based detectors. Although these states are unbound to particle decay, all channels with significant penetrabilities are isospin forbidden, so that gamma decay is a possibility. Our results indicate that these states decay mainly by neutron emission and therefore contribute very little to detection sensitivities for Ga71 and Br81