First direct double-β decay Q-value measurement of Se82 in support of understanding the nature of the neutrino

In anticipation of results from current and future double-β decay studies, we report a measurement resulting in a Se82 double-β decay Q value of 2997.9(3) keV, an order of magnitude more precise than the currently accepted value. We also present preliminary results of a calculation of the Se82 neutrinoless double-β decay nuclear matrix element that corrects in part for the small size of the shell model single-particle space. The results of this work are important for designing next generation double-β decay experiments and for the theoretical interpretations of their observations.