Speaker
Description
Double beta plus decay is a rare nuclear process whose neutrinoless mode would provide evidence for lepton number violation and the Majorana nature of neutrinos. Experimental searches are particularly challenging due to the low decay rates, limited isotope abundances, and complex event signatures involving positrons and annihilation photons.
NuDoubt$^{++}$ is a hybrid opaque scintillation detector concept developed for double beta plus decay searches in $^{78}$Kr. In the opaque scintillation approach, light emission from an energy deposit remains localized, enabling the reconstruction of individual deposits using a volumetric readout with wavelength-shifting fibers. Combined with the detection of both scintillation and Cherenkov light, this allows for enhanced positron identification and improved background suppression.
This work focuses on Monte Carlo simulations used to model detector response, characterize signal and background topologies, and evaluate the experiment’s projected sensitivity. Initial studies indicate that NuDoubt$^{++}$ could achieve sensitivity to two-neutrino double beta plus decay in $^{78}$Kr with exposures on the order of 1 tonne-week, while also substantially extending current limits on the neutrinoless decay mode.