Observables in Neutrino Mass Spectroscopy Using Atoms

Abstract

We discuss how the absolute neutrino mass scale, the neutrino mass hierarchy and the nature (Dirac or Majorana) of massive neutrinos can be determined, in principle, from the measurement of the continuous spectrum of the photon produced in the process of collective de-excitation of atoms in a metastable level into emission mode of a single photon plus a neutrino pair ("radiative emission of neutrino pair (RENP)"). We use the example of a transition between specific levels of the Yb atom. The possibility of determining the nature of massive neutrinos and, if neutrinos are Majorana fermions, of obtaining information about the Majorana phases in the neutrino mixing matrix, is analised in the cases of normal hierarchical, inverted hierarchical and quasi-degenerate types of neutrino mass spectrum. It is found, in particular, that the sensitivity to the nature of massive neutrinos depends critically on the atomic level energy difference relevant in the RENP.