FIMP dark matter and low scale leptogenesis in an extended neutrino two Higgs doublet model($ u$2HDM)

We have studied dark matter (DM) phenomenology, neutrinoless double beta decay (NDBD) and realised low scale leptogenesis in a simple extension of Standard Model(SM) with three neutral fermions, a scalar doublet and a dark sector incorporating a singlet scalar and a Dirac singlet fermion. A generic model based on $A_4 otimes Z_4$ flavor symmetry is used to explain both normal and inverted hierarchy mass pattern of neutrino and also to accommodate the dark matter mass. In this extension of the $ u$2HDM, the effective neutrino mass observed in 0$ ubetabeta$ is well within the experimental limit provided by KamLAND-ZEN. In order to validate DM within this model, we have checked relic abundance and free streaming length of the dark sector component, i.e. a Dirac singlet fermion constraining its mass in keV range. More importantly we have also realised low scale leptogenesis simultaneously within this framework and also the Dirac CP phase gets constrained with the results. Co-relation among the observable and model parameters are also carried out within this framework.