Double beta decays and neutrino nuclear responses

Neutrino-less double beta decays (0 nu beta beta), which violate the lepton number conservation law by Delta L = 2, are unique and realistic probes for studying the Majorana nature of neutrinos, the v mass spectrum and the absolute mass scale, the lepton sector CP and others beyond the standard electro-weak theory. Neutrino nuclear responses (nuclear matrix elements M(0 nu)) are crucial to extract neutrino properties of the particle physics interests from experimental 0 nu beta beta rates. Subjects discussed include 0 nu beta beta processes and Majorana neutrinos, the present and future 0 nu beta beta experiments, and neutrino nuclear responses (M) and charge exchange reactions. (C) 2010 Elsevier By. All rights reserved.