(a) KamLAND-ZEN detector; see text for a description (figure from [132]). (b) KamLAND-ZEN result (figure from [134]). In the left panel (A) the energy spectrum of selected candidate events together with the best-fit backgrounds and decays, and the 90% C.L. lower limit for decays. In the right panel (B), a close-up of (A) region after subtracting known background contributions.
