Joint Nuclear Physics and Particle Physics Seminar
"Understanding the nature of neutrinos via neutrinoless double-beta decay"
Presented by Wenqin Xu, Los Alamos National Laboratory
11 am, Small Seminar Room, Bldg. 510
Tuesday, September 8, 2015, 11:00 am
Hosted by: Jin Huang
Neutrinos provide a critical portal to physics beyond the Standard Model, yet the nature of neutrinos is largely unknown, including the neutrino mass hierarcy and if neutrinos are Majorana particles. Majorana particles are fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and would pave the way to understand the matter-antimatter asymmetry in the universe. Neutrinoless double-beta (0) decay is a hypothesized process where two neutrons decay into two protons and two electrons simultaneously without emitting neutrinos. It is possible only if neutrinos are Majorana particles, and it is the only feasible way to experimentally establish the Majorana or Dirac nature of neutrinos. The observation of 0 decay would also provide complementary information related to neutrino masses. After decades of experimental eorts, the next generation 0 decay experiments will have a signicant discovery potential to observe 0 decay, if neutrinos are indeed Majorana particles. In this talk, we will discuss the physics of neutrinoless double beta decay and review the experiments searching for it. We will focus on the Majorana Demonstrator, a 40-kg modular Germanium detector array, which searches for 0 decay in 76Ge and aims at demonstrating a path forward to next generation 0 decay experiments.