Leptogenesis in SO(10) with Minimal Yukawa sector

TL;DR

This paper demonstrates that a minimal $SO(10)$ Yukawa sector can successfully fit fermion masses, mixings, and reproduce the observed baryon asymmetry via leptogenesis, aligning with current experimental constraints.

Contribution

It provides the first comprehensive fit within a minimal $SO(10)$ framework that accounts for fermion data and cosmological baryon asymmetry simultaneously.

Findings

Hierarchical right-handed neutrino masses favor $N_2$-dominated leptogenesis.

Fits accommodate both normal and inverted neutrino mass orderings.

Leptonic CP phase prefers values between 230° and 300°.

Abstract

In prior studies, a very minimal Yukawa sector within the $SO(10)$ Grand Unified Theory framework has been identified, comprising of Higgs fields belonging to a real $10_H$, a real $120_H$, and a $\overline{126}_H$ dimensional representations. In this work, within this minimal framework, we have obtained fits to fermion masses and mixings while successfully reproducing the cosmological baryon asymmetry via leptogenesis.The right-handed neutrino ($N_i$) mass spectrum obtained from the fit is strongly hierarchical, suggesting that $B-L$ asymmetry is dominantly produced from $N_2$ dynamics while $N_1$ is responsible for erasing the excess asymmetry. With this rather constrained Yukawa sector, fits are obtained both for normal and inverted ordered neutrino mass spectra, consistent with leptonic CP-violating phase $\delta_\mathrm{CP}$ indicated by global fits of neutrino oscillation data, while also satisfying the current limits from neutrinoless double beta decay experiments. In particular, the the leptonic CP-violating phase has a preference to be in the range $\delta_\mathrm{CP}\simeq (230-300)^\circ$. We also show the consistency of the framework with gauge coupling unification and proton lifetime limits.