2023/12/22 by Lukáš Gráf, Gráf, Lukáš, Sudip Jana +5 · 2 citations
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.2312.15016
openalex publication_date 2023/12/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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.