Speaker
Description
In Low scale leptogenesis(LSL) models a small RH neutrino mass can dynamically be generated if there is a weak coupling between a long-lived scalar field and RH neutrinos despite having a large VEV, $v_\Phi$. In such a scenario, the correlation shared by the non-standard scalar era driven by $\Phi$ and $M_i$s provides an excellent opportunity to study the fingerprints of LSL on primordial gravitational waves. We study the gravitational waves originating due to the inflationary blue-tiled tensor power spectrum and propagating through the scalar epoch, which depending upon $M_i$s provides two significant insights. Firstly, taking LSLs seriously even for very high scale reheating GWs with a significant blue-tilt don’t violate the BBN bound. Secondly, it unravels an opportunity to test LSLs via a low frequency and complementary high frequency doubly peaked GW background. Taking recent results on GWs from PTAs at face value and taking it as a measure at low frequencies allows one to get possible signatures of LSL mechanisms at higher frequencies.
| Session | Astroparticle Physics and Cosmology |
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