The calculation of molecular final states and their effect on a precision neutrino mass experiment

An experiment to determine the electron neutrino mass with the precision of a few eV by measuring the tritium beta decay distribution near the endpoint is being performed at the Lawrence Livermore National Laboratory. At the few eV level, a major consideration in the choice of a tritium source is the effect of excited final molecular states on the beta decay distribution. It is important to choose a source for which the initial and final states can be accurately calculated. The authors have chosen frozen tritium as their source since states of molecular tritium and those of the HeT/sup +/ daughter ion have molecular wavefunctions that can be calculated with high accuracy. They describe the effects of final excited states on the neutrino mass determination and the results of their calculations in this paper