Speaker
Description
We investigate the possibility of neutrinoless double beta decay $( 0 \nu \beta\beta)$ and leptogenesis within a low-scale seesaw mechanism with additional sterile neutrinos. The general effective field theory (EFT) considerations suggest that if there are experimentally observable signatures in $0 \nu \beta \beta$-decay and the lepton asymmetry generated by the right-handed neutrinos, the low-scale leptogenesis is likely to be unviable.
However, in this work, we show that in the context of low-scale resonant leptogenesis, one can obtain the observed BAU and observable signatures of $0 \nu \beta \beta$ decay in the presence of additional sterile neutrinos. In this framework, the neutrino masses are suppressed by the extended seesaw parameter, $\mu$, rather than introducing small Yukawa couplings in other leptogenesis scenarios. These large Yukawa couplings in this model can lead to both observable experimental signatures in $0\nu\beta\beta$ decay and large washout effects. The resonant leptogenesis mechanism with light neutrino masses can overcome the latter, even in the presence of experimentally accessible $0\nu\beta\beta$-decay signatures.
We have shown that the KamLAND-Zen experiment is sensitive to MeV-scale sterile neutrinos, and future ton-scale experiments offer potential signals while maintaining viable leptogenesis.
