Towards Precision Neutrino Fits in GUTs: Relevance of One-Loop Finite Corrections

Abstract

In this work, we perform a dedicated analysis of fermion mass fits in the minimal $SO(10)$ grand unified theory (GUT), going beyond the tree-level approximation by incorporating one-loop finite corrections to the neutrino mass matrix. We show that parameter regions that successfully reproduce all fermion masses and mixings at tree level can lead to significant deviations in neutrino masses and leptonic mixing parameters once the radiative corrections are included. These results expose a limitation of conventional tree-level fitting procedures and highlight the sensitivity of neutrino observables to loop effects. Since in the minimal $SO(10)$ GUT the same set of Yukawa parameters simultaneously governs quark masses, charged lepton masses, and neutrino properties, these radiative corrections propagate across all fermion sectors, reshaping the viable parameter space in a highly non-trivial and correlated manner. We find that the largest corrections to the masses and mixing angles are of order $\mathcal{O}(30\%)$-$\mathcal{O}(40\%)$, therefore, cannot be neglected. In light of the current precision of neutrino oscillation measurements, and the expected improvements from ongoing and future experiments, we demonstrate that the inclusion of one-loop effects is essential for a consistent and reliable exploration of the parameter space, with important implications for the predictivity of $SO(10)$ GUTs.