# High scale flavor alignment in two-Higgs doublet models and its phenomenology

## TL;DR

This paper investigates the implications of high-scale flavor alignment in two-Higgs doublet models, analyzing how renormalization group effects generate flavor-changing neutral currents and constraining the model with current experimental data.

## Contribution

It introduces a high-scale flavor alignment framework in 2HDMs and studies the resulting flavor-changing effects and phenomenological constraints.

## Key findings

- Flavor-changing neutral currents are generated via RG running from high scale.
- Constraints on 2HDM parameters are derived from flavor observables.
- Implications for Higgs phenomenology are analyzed within the aligned model.

## Abstract

The most general two-Higgs doublet model (2HDM) includes potentially large sources of flavor changing neutral currents (FCNCs) that must be suppressed in order to achieve a phenomenologically viable model. The flavor alignment ansatz postulates that all Yukawa coupling matrices are diagonal when expressed in the basis of mass-eigenstate fermion fields, in which case tree-level Higgs mediated FCNCs are eliminated. In this work, we explore models with the flavor alignment condition imposed at a very high energy scale, which results in the generation of Higgs-mediated FCNCs via renormalization group running from the high energy scale to the electroweak scale. Using the current experimental bounds on flavor changing observables, constraints are derived on the aligned 2HDM parameter space. In the favored parameter region, we analyze the implications for Higgs boson phenomenology.