The Department of Physics, School of Natural Sciences, invites you to a seminar on Search for Neutrinoless Double-Beta Decay

Abstract:

Are neutrinos their own antiparticles? The search for an extremely rare and yet unobserved nuclear transition−neutrinoless double-beta (0νββ) decay is ongoing. The observation would prove neutrinos and antineutrinos are identical particles−Majorana neutrinos. This decay violates lepton number conservation and therefore provides a plausible scenario to interpret the matter-antimatter asymmetry in the Universe. Neutrino oscillation proves neutrinos are massive, but the absolute neutrino masses are yet unknown. 0νββ decay constrains or measures the effective Majorana neutrino mass. The experimental search for the signal of this decay is extremely challenging as it requires a quasi-background-free experiment. The new experiment LEGEND-200 has recently begun collecting physics data using the 76Ge isotope. Its first results show no evidence for a 0νββ signal, setting a new observed lower limit on the half-life at T0ν_{1/2} > 1.9×10^{26} yr and a corresponding upper limit on the effective Majorana mass in the range mββ < 75 − 200 meV. Next-generation ton-scale experiments—LEGEND-1000, KamLAND2-Zen, nEXO, SNO+, CUPID are currently planned. In this talk, I will provide an introductory aspect of neutrinoless double-beta decay and an overview of the different planned experiments, with a particular emphasis on LEGEND-1000.

All are cordially invited.