Neutrinoless Double Beta Decay without Vacuum Majorana Neutrino Mass

Fuente: arXiv
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Main Authors: Gráf, Lukáš, Jana, Sudip, Scholer, Oliver, Volmer, Nele
Format: Preprint
Published: 2023
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author Gráf, Lukáš
Jana, Sudip
Scholer, Oliver
Volmer, Nele
author_facet Gráf, Lukáš
Jana, Sudip
Scholer, Oliver
Volmer, Nele
contents We present a proof-of-concept extension to the Standard Model that can generate a non-vanishing neutrinoless double beta decay ($0νββ$) signal without the existence of Majorana neutrinos or lepton number violation in the zero-density vacuum-ground-state Lagrangian. We propose that the $0νββ$ can be induced by the capture of an ultralight scalar field, a potential dark matter candidate, that carries two units of lepton number. This makes the observable $0νββ$ spectrum indistinguishable from the usual $0νββ$ mechanisms by any practical means. We find that a non-zero $0νββ$ rate does not require neutrinos to be fundamentally Majorana particles. However, for sizeable decay rates within the range of next-generation experiments, the neutrino will, generally, acquire an (effective) Majorana mass as the scalar field undergoes a transition to the Bose-Einstein condensate phase. We also discuss the distinction between the aforementioned scenario and the case in which the emission of a lepton-number-two scalar leads to $0νββ$, exhibiting discernible qualitative features that make it experimentally distinguishable from the conventional scenario.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15016
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Neutrinoless Double Beta Decay without Vacuum Majorana Neutrino Mass
Gráf, Lukáš
Jana, Sudip
Scholer, Oliver
Volmer, Nele
High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Theory
We present a proof-of-concept extension to the Standard Model that can generate a non-vanishing neutrinoless double beta decay ($0νββ$) signal without the existence of Majorana neutrinos or lepton number violation in the zero-density vacuum-ground-state Lagrangian. We propose that the $0νββ$ can be induced by the capture of an ultralight scalar field, a potential dark matter candidate, that carries two units of lepton number. This makes the observable $0νββ$ spectrum indistinguishable from the usual $0νββ$ mechanisms by any practical means. We find that a non-zero $0νββ$ rate does not require neutrinos to be fundamentally Majorana particles. However, for sizeable decay rates within the range of next-generation experiments, the neutrino will, generally, acquire an (effective) Majorana mass as the scalar field undergoes a transition to the Bose-Einstein condensate phase. We also discuss the distinction between the aforementioned scenario and the case in which the emission of a lepton-number-two scalar leads to $0νββ$, exhibiting discernible qualitative features that make it experimentally distinguishable from the conventional scenario.
title Neutrinoless Double Beta Decay without Vacuum Majorana Neutrino Mass
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Theory
url https://arxiv.org/abs/2312.15016