Speaker
Description
We explore the connection between the low-scale CP-violating Dirac phase $(\delta)$ and high-scale leptogenesis in a Left-Right Symmetric Model (LRSM) with scalar bidoublets and doublets. The model's fermion sector includes one sterile neutrino $(S_L)$ per generation, enabling a double seesaw mechanism. This mechanism, performed via type-I seesaw twice, generates a Majorana mass term for heavy right-handed (RH) neutrinos $(N_R)$, with the light neutrino mass linearly dependent on the $S_L$ mass. Assuming charge conjugation ($C$) as the discrete left-right (LR) symmetry helps derive the Dirac neutrino mass matrix ($M_D$) in terms of the light and heavy RH neutrino masses and the light neutrino mixing matrix $U_{PMNS}$ (containing $\delta$). We illustrate the viability of unflavored thermal leptogenesis via the decay of RH neutrinos using the obtained $M_D$ with RH neutrino masses as inputs. Our analysis of the Boltzmann equations shows that the CP-violating Dirac phase alone can produce the required leptonic asymmetry. Importantly, we highlight that current and near-future oscillation experiments, like DUNE, aiming to refine $\delta$, can potentially constrain our model and thus serve as a probe for early Universe leptogenesis indirectly.
| Working Group | WG 1: Neutrino Oscillation Physics |
|---|