Natural Alignment of Quark Flavors and Radiatively Induced Quark Mixings

TL;DR

This paper proposes a model combining left-right and Peccei-Quinn symmetries to explain quark flavor alignment and small quark mixings via radiative corrections, while addressing the strong CP problem.

Contribution

It introduces a novel framework where quark mixings are radiatively generated and links flavor alignment to symmetry principles, also solving the strong CP problem.

Findings

Quark mixings arise from one-loop radiative corrections.

Neutrino masses fit with seesaw mechanism requiring >18 TeV $W_R$ mass.

Model successfully fits fermion masses and mixings.

Abstract

The standard model does not provide an explanation of the observed alignment of quark flavors i.e. why are the up and down quarks approximately aligned in their weak interactions according to their masses? We suggest a resolution of this puzzle using a combination of left-right and Peccei-Quinn (PQ) symmetry. The quark mixings in this model vanish at the tree level and arise out of one loop radiative corrections which explains their smallness. The lepton mixings on the other hand appear at the tree level and are therefore larger. We show that all fermion masses and mixings can be fitted with a reasonable choice of parameters. The neutrino mass fit using seesaw mechanism requires the right handed $W_R$ mass bigger than 18 TeV. Due to the presence of PQ symmetry, this model clearly provides a solution to the strong CP problem.