Double Beta Decay of $^{150}$Nd to Excited Final States

Studying $\beta\beta$ decay with emission of neutrinos (2$\nu\beta\beta$) in particular is important as a check for theoretical models which can be used to predict the half-lives of neutrinoless $\beta\beta$ decay (0$\nu\beta\beta$). Results from studying 2$\nu\beta\beta$ decay can aid in the search for 0$\nu\beta\beta$ decay, which in turn can provide information on the fundamental properties of the neutrino. Because SNO+ and KamLAND plan to use $^{150}$Nd as a nuclide in searches for 0$\nu\beta\beta$ decay, our goal is to measure the 2$\nu\beta\beta$ decay of $^{150}$Nd to the first excited 0$^+$ state in $^{150}$Sm. In QRPA models, the calculated matrix elements for transitions to the ground state and excited states depend in a very different way on the so-called g$_{pp}$ parameter. Therefore, 2$\nu\beta\beta$ decay data to excited states are of special interest. Such data exist only for $^ {100}$Mo; only tentative information is available for $^{150} $Nd. Thus, we report on our preliminary studies and our plans for observing the decay of $^{150}$Nd to the first excited 0 $^+$ state in $^{150}$Sm by detecting the 334 keV and 406.5 keV deexcitation gamma rays in coincidence.