b → sγ, electron EDM, and electroweak baryogenesis: a study in 2HDM

We study inclusive b → sγ decay in the context of electron EDM and baryogenesis. The { general} 2HDM (i.e.~without Z₂) that possesses an extra set of Yukawa matrices can drive electroweak baryogensis via λₜ Imρₜₜ, where ρₜₜ is the extra diagonal top Yukawa coupling, with the eEDM constraint evaded by an exquisite flavor cancellation mechanism. We touch upon the current status of direct search for exotic H, A and H⁺ scalars at the LHC, while for the plethora of flavor observables in g2HDM, we focus on b→ sγ, pointing out { chiral} enhancement of a ρₜₜρbb effect in { g}2HDM, which can bring in a CPV phase. We first explore the inclusive B(b → sγ) rate, then showcase the progress that Belle~II can make in the future, illustrating a potential 3σ effect for the inclusive B⁺ → Xₛ⁺γ vs B⁰ → Xₛ⁰γ CPV rate difference, Δ ACP. Especially if eEDM emerges swiftly, perhaps one should pursue further upgrade beyond Belle~II.