DPF - PHENO 2024

Baryon asymmetry from dark matter decay in the vicinity of a phase transition

14 May 2024, 17:00

15m

Barco Law Building 107 (University of Pittsburgh)

Cosmology & Dark Energy Cosmology & Dark Energy

Speaker

Indrajit Saha (IIT Guwahati, India)

Description

We propose a novel framework where baryon asymmetry of the universe can arise due to forbidden decay of dark matter (DM) enabled by finite-temperature effects in the vicinity of a first order phase transition (FOPT). In order to implement this novel cogenesis mechanism, we consider the extension of the standard model by one scalar doublet $\eta$, three right handed neutrinos (RHN), all odd under an unbroken $Z_2$ symmetry, popularly referred to as the scotogenic model of radiative neutrino mass. While the lightest RHN $N_1$ is the DM candidate and stable at zero temperature, there arises a temperature window prior to the nucleation temperature of the FOPT assisted by $\eta$, where $N_1$ can decay into $\eta$ and leptons generating a non-zero lepton asymmetry which gets converted into baryon asymmetry subsequently by sphalerons. The requirement of successful cogenesis together with a first order electroweak phase transition not only keep the mass spectrum of new particles in sub-TeV ballpark within reach of collider experiments but also leads to observable stochastic gravitational wave spectrum which can be discovered in planned experiments like LISA.

Presentation materials

DPF_Pheno_Indrajit.pdf