Anomalous B meson mixing and baryogenesis in a two Higgs doublet model with top-charm flavor violation

Abstract

There exist experimental hints from the B sector for CP violation beyond the Standard Model (SM) CKM paradigm. An anomalous dimuon asymmetry was reported by the D0 collaboration, while tension exists between $B\to \tau \nu$ and $S_{\psi K}$. These measurements, disfavoring the SM at the ~3$\sigma$ level, can be explained by new physics in both $B_d$-${\bar{B}}_d$ and $B_s$- ${\bar{B}}_s$ mixing, arising from (1) new bosonic degrees of freedom at or near the electroweak scale, and (2) new, large CP-violating phases. These two new physics ingredients are precisely what is required for electroweak baryogenesis to work in an extension of the SM. We show that a simple two Higgs doublet model with top-charm flavor violation can explain the B anomalies and the baryon asymmetry of the Universe. Moreover, the presence of a large relative phase in the top-charm Yukawa coupling, favored by $B_{d,s}$-${\bar{B}}_{d,s}$ mixing, weakens constraints from ${ϵ}_K$ and $b\to s\gamma$, allowing for a light charged Higgs mass of O(100 GeV).

Comments: 8 pages, 5 figures