# The direct CP violation in a general two Higgs doublet model

## TL;DR

This paper investigates how a general two-Higgs-doublet model with flavor-changing neutral currents can account for observed CP violation in meson decays and proposes experimental tests at the LHC.

## Contribution

It introduces a comprehensive analysis of CP violation in a general 2HDM with sizable Yukawa couplings, addressing flavor anomalies and suggesting collider tests.

## Key findings

- The model can significantly contribute to CP violation in K and B meson decays.
- It potentially explains the discrepancy in direct CP violation in K meson decays.
- Proposes experimental strategies to test the 2HDM at the LHC.

## Abstract

In this paper, we study the CP violating processes in a general two-Higgs-doublet model (2HDM) with tree-level flavor changing neutral currents. In this model, sizable Yukawa couplings involving top and charm quarks are still allowed by the collider and flavor experiments, while the other couplings are strongly constrained experimentally. The sizable couplings, in general, have imaginary parts and could largely contribute to the CP violating observables concerned with the $B$ and $K$ mesons. In particular, the contribution may be so large that it affects the direct CP violating $K$ meson decay, where the discrepancy between the experimental result and the Standard Model prediction is reported. We discuss how well the anomaly is resolved in the 2HDM, based on study of the other flavor observables. We also propose the way to test our 2HDM at the LHC.