Probing Yukawa Unification with K and B Mixing

TL;DR

This paper investigates how supersymmetric grand unified theories with Yukawa coupling corrections influence meson mixing and CP violation, constraining flavor structure through K and B meson data.

Contribution

It provides a detailed analysis of flavor constraints on Yukawa unification corrections in a SUSY-SO(10) model, linking neutrino mixing to meson transitions.

Findings

epsilon_K constrains the right-handed squark mixing angle to about 1 degree.

Large neutrino mixings can impact the unitarity triangle analysis.

The model can potentially explain the observed CP violation in B_s -> psi phi decays.

Abstract

We consider corrections to the unification of down-quark and charged-lepton Yukawa couplings in supersymmetric GUTs, which links the large nu_tau-nu_mu mixing angle to b -> s transitions. These corrections generically occur in simple grand-unified models with small Higgs representations and affect s -> d and b -> d transitions via the mixing of the corresponding right-handed superpartners. On the basis of a specific SUSY-SO(10) model, we analyze the constraints from K-Kbar and B-Bbar mixing on the additional \tilde{d}_R-\tilde{s}_R rotation angle theta. We find that epsilon_K already sets a stringent bound on theta, theta^{max}=O(1 degree), indicating a very specific flavor structure of the correction operators. The impact of the large neutrino mixings on the unitarity triangle analysis is also briefly discussed, as well as their ability to account for the sizeable CP-violating phase observed recently in B_s -> psi phi decays.