# Phenomenology of the Partially Aligned 2HDM with leptonic decay of mesons

## TL;DR

This paper analyzes the phenomenology of the Partially Aligned 2HDM using leptonic meson decays and meson mixing, highlighting flavor symmetry effects and providing bounds and predictions for new physics contributions.

## Contribution

It introduces a scenario where flavor symmetry controls FCNC without Yukawa alignment, and derives bounds and predictions for leptonic meson decays within this framework.

## Key findings

- Bounds on model parameters from meson decay data.
- Predictions for leptonic decay branching ratios with FCNC and LFV.
- Constraints linking quark and lepton sectors in the model.

## Abstract

In this paper we present a phenomenological analysis of the Partially Aligned Two Higgs Doublet Model (PA-2HDM) by using leptonic decays of mesons and $B^0_{d,s}$-$\bar B^0_{d,s}$ mixing. We focus our attention in a scenario where the leading contribution to FCNC is given by the tree level interaction with the light pseudoscalar $A^0$ ($M_{A^0}\sim 250$ GeV). We show how an underlying flavor symmetry controls FCNC in the quark and lepton couplings with the pseudoscalar, without alignment between Yukawa matrices. Upper bounds on the free parameters are calculated in the context of the leptonic decays $B^0_{s,d}\to\mu^+\mu^-$ and $K^0_L\to \mu^+\mu^-$ and $B^0_{s,d}$ mixing. Also, our assumptions implies that bounds on New Physics contribution in the quark sector coming from $B^0_{s,d}$ mixing impose an upper bound on the parameters for the leptonic sector. Finally we give predictions of branching ratios for leptonic decay of mesons with FCNC and LFV.