Electroweak Baryogenesis in Two Higgs Doublet Models and B meson anomalies

TL;DR

This paper investigates whether two Higgs doublet models can simultaneously explain the B meson dimuon anomaly and achieve successful electroweak baryogenesis, finding limited parameter space where both can be addressed.

Contribution

It provides a comprehensive analysis of 2HDMs, including constraints and numerical scans, revealing the narrow conditions under which EWBG and B physics anomalies can coexist.

Findings

Large baryon asymmetry only in small parameter space

Tension between explaining dimuon anomaly and baryogenesis

Predictive collider signatures for EWBG-compatible models

Abstract

Motivated by 3.9 sigma evidence of a CP-violating phase beyond the standard model in the like-sign dimuon asymmetry reported by DO, we examine the potential for two Higgs doublet models (2HDMs) to achieve successful electroweak baryogenesis (EWBG) while explaining the dimuon anomaly. Our emphasis is on the minimal flavour violating 2HDM, but our numerical scans of model parameter space include type I and type II models as special cases. We incorporate relevant particle physics constraints, including electroweak precision data, b to s gamma, the neutron electric dipole moment, R_b, and perturbative coupling bounds to constrain the model. Surprisingly, we find that a large enough baryon asymmetry is only consistently achieved in a small subset of parameter space in 2HDMs, regardless of trying to simultaneously account for any B physics anomaly. There is some tension between simultaneous explanation of the dimuon anomaly and baryogenesis, but using a Markov chain Monte Carlo we find several models within 1 sigma of the central values. We point out shortcomings with previous studies that reached different conclusions. The restricted parameter space that allows for EWBG makes this scenario highly predictive for collider searches. We discuss the most promising signatures to pursue at the LHC for EWBG-compatible models.