Search for Light Exotic Fermions in Double-Beta Decays

Abstract

The Standard Model of Particle Physics predicts the double-$\beta$ decay of certain nuclei with the emission of two active neutrinos. In this letter, we argue that double-$\beta$ decay experiments could be used to probe models with light exotic fermions through the search for spectral distortions in the electron spectrum with respect to the Standard Model expectations. We consider two concrete examples: models with light sterile neutrinos, singly produced in the double-$\beta$ decay, and models with a light $Z_2$-odd fermion, pair produced due to a $Z_2$ symmetry. We estimate the discovery potential of a selection of double-$\beta$ decay experiments and find that future searches will test for the first time a new part of the parameter space of interest at the MeV-mass scale.

9 pages, 3 figures. Matches published version

References in corpus (7)

• Energy density functional study of nuclear matrix elements for neutrinoless $\beta \beta$ decay
• $0\nu \beta \beta$ and $2\nu \beta \beta$ nuclear matrix elements in the interacting boson model with isospin restoration
• Nuclear matrix element of neutrinoless double-$\beta$ decay: Relativity and short-range correlations
• Phase space factors for ${\beta }^{+}{\beta }^{+}$ decay and competing modes of double-$\beta$ decay
• Revisiting cosmological bounds on sterile neutrinos
• Neutrino Self-Interactions and Double Beta Decay
• Detecting sterile neutrinos with KATRIN like experiments