# Alignment of Yukawa couplings in two Higgs doublet models

**Authors:** Seong Youl Choi, Jae Sik Lee, Jubin Park  
**arXiv:** [2011.04978](https://arxiv.org/abs/2011.04978)  
**Date:** 2020-11-10  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2011.04978v1/

## Key points

- Study by Choi, Lee, and Park on alignment of Yukawa couplings in 2HDMs
- Investigation of alignment without decoupling in type-I 2HDMs
- Findings suggest easy attainment of alignment with minimal conflict with current LHC Higgs precision data
- Observation that lightest Higgs boson's Yukawa couplings exhibit slower decoupling compared to coupling to massive vector bosons
- Identification of wrong-sign alignment limit for Yukawa couplings in certain scenarios
- Research provides insights into different scenarios' impact on compatibility with LHC Higgs precision data

## Summary

In their study, Seong Youl Choi, Jae Sik Lee, and Jubin Park delve into the alignment of Yukawa couplings within the framework of general two Higgs doublet models (2HDMs). Specifically focusing on a scenario where the lightest neutral Higgs boson is purely CP even, they allow for mixing between the two heavier neutral Higgs bosons in the presence of nontrivial CP-violating phases in the Higgs potential. By identifying the lightest neutral Higgs boson as the 125 GeV particle discovered at the LHC, they investigate how alignment of Yukawa couplings can be achieved without decoupling in type-I 2HDMs. Their findings suggest that this alignment can be easily attained with minimal conflict with current LHC Higgs precision data. Furthermore, Choi et al. observe that in cases where decoupling does not occur, the Yukawa couplings of the lightest Higgs boson exhibit slower decoupling compared to its coupling to massive vector bosons. This results in significant deviations from Standard Model (SM) values even when deviations in Higgs-to-vector-boson coupling are below one percent. Regardless of 2HDM type and decoupling status, they also identify a wrong-sign alignment limit for Yukawa couplings. In this scenario, the strengths of Yukawa couplings to down-type quarks and/or charged leptons are equal but opposite in sign to their SM counterparts, while up-type quark Yukawa couplings remain unchanged from SM predictions. Overall, Choi, Lee, and Park's research highlights various possibilities for aligning Yukawa couplings within 2HDMs and presents insights into how different scenarios impact compatibility with LHC Higgs precision data. Their comprehensive analysis contributes valuable information to our understanding of these complex models and their implications for particle physics research.