Abstract
We consider new modes of two-neutrino and neutrinoless double-$\beta$ decays in which one $\beta$ electron goes over to a continuous spectrum and the other occupies a vacant bound level of the daughter ion. We calculate the corresponding phase-space factors of the final states, estimate the partial decay rates, and derive the one- and two-electron energy spectra using relativistic many-electron wave functions of atoms provided by the multiconfiguration Dirac-Hartree-Fock package GRASP2K. While the bound-state neutrinoless double-$\beta$ decays are strongly suppressed, their two-neutrino counterparts can be observed in the next-generation double-$\beta$-decay experiments, most notably SuperNEMO.
Highlights
While the bound-state neutrinoless double-β decays are strongly suppressed, their two-neutrino counterparts can be observed in the next-generation double-β-decay experiments, most notably SuperNEMO
Among the most challenging problems of modern neutrino physics are the mechanism of neutrino mixing and the nature of neutrino masses (Dirac or Majorana)
G0ν (2ν )ββ which are independent of the nuclear matrix elements (NMEs) and mββ, and are free of uncertainties inherent in the nuclear-structure models and neutrino masses
Summary
Among the most challenging problems of modern neutrino physics are the mechanism of neutrino mixing and the nature of neutrino masses (Dirac or Majorana). Measurement of the half-life of the 0νββ decay could provide a key to the absolute scale of neutrino masses and shed light on the leptonic CP violation mechanism required to explain the observed baryon asymmetry of the Universe [2,3]. The 2νββ decay occurs in the second order of weak interaction and as such it conserves the total lepton number: L = 0. +2, and requires a Majorana mass term This process could be observed as a monoenergetic peak at the 2νββ spectrum endpoint in calorimetric measurements of the sum of electron energies. The neutrinoless double-β decay with two bound electrons in the final state denoted by 0νEPEP (where EP stands for the “electron placement”). We develop a formalism for description of the bound-state two-neutrino and neutrinoless double-β decays denoted by 0ν(2ν)EPβ: νe ). VI, we draw conclusions regarding possible experimental observation of the bound-state double-β decays and provide motivation for further studies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
