H. Song: Getting Excited About Double Beta Decay in KamLAND-ZEN

Neutrinos remain the least understood component of the Standard Model of Particle Physics. Basic fundamental questions about neutrino nature have yet to be answered. Questions like, what is the neutrino mass? By what mechanism do neutrinos attain mass? And could the neutrino be its own anti-particle? Searches for the rare nuclear decay process neutrino-less double beta decay (0vBB) hope to answer many of these questions in one stroke. The KamLAND-ZEN experiment has set the world-leading limit on this rare theorized process. But, large uncertainties in theoretical nuclear matrix element calculations hinder our interpretation of this result. In this talk, I will present the work done on a complementary physics search, double beta decay to excited states (2vBB*). A secondary goal of KamLAND-ZEN, a measurement of this Standard Model decay could inform theoretical nuclear matrix element calculations, and reduce theoretical systematic uncertainties. I describe work done to characterize the major backgrounds and preliminary limits on (2vBB*).