Flavor Physics Constraints on Left-Right Symmetric Models with Universal Seesaw

TL;DR

This paper investigates constraints on left-right symmetric models with universal seesaw mechanisms, focusing on flavor-changing processes and their implications for flavor anomalies and muon g-2.

Contribution

It provides a detailed phenomenological analysis of flavor constraints in parity symmetric left-right models with universal seesaw, highlighting their limitations in explaining certain flavor anomalies.

Findings

Flavor changing neutral currents impose strong constraints on the model.

The model cannot explain B-anomalies R_{K^{(*)}}.

The model does not resolve the muon g-2 discrepancy.

Abstract

We study the phenomenological constraints on the parameter space in the parity symmetric scenario of a class of left-right symmetric models in which the fermion masses are generated through a universal seesaw mechanism. The model, motivated by the axionless solution to the strong $\mathcal{CP}$ problem, has a simple Higgs sector consisting of left- and right-handed doublets. The fermion masses are then generated through their mixing with heavy vector-like fermions, which leads to flavor changing neutral currents arising at tree-level and also introduces non-unitarity in the charged current interactions. These new contributions lead to flavor and flavor universality violating processes and forbidden decays, which are used to derive constraints on the parameter space of the model. We also argue that although the model has the potential to resolve flavor anomalies, it fails to do so in the case of B-anomalies $R_{K^{(*)}}$ and anomalous magnetic moment of muon $(g-2)_\mu$.