Flavor and CP Violation with Fourth Generations Revisited

الأصل · EN

The Standard Model predicts a very small CP violation phase 2Φ SMBₛ ≃ -0.04%= M₁₂ ≃ (V*tsVtb)² in Bₛ-- Bₛ mixing. %, i.e. of order λ²η. Any finite value of ΦBₛ measured at the Tevatron would imply New Physics. With recent hints for finite 2ΦBₛ, % have appeared from CDF and DØ experiments at the Tevatron, we reconsider the possibility of a 4th generation. As recent direct search bounds have become considerably heavier than 300 GeV, we take the t' mass to be near the unitarity bound of 500 GeV. Combining the measured values of ΔmBₛ with B(B → Xₛℓ+ℓ-), together with typical fBₛ values, we find a sizable 2Φ SM4Bₛ -0.33. Using %a typical value of mb' = 480 GeV, we extract the range % a range of values, 0.06 < |Vₜ'b| < 0.13 from the constraints of Γ(Z→ b b), ΔmD and B(K+→π+νν). A future measurement of B(Kₗ→π⁰νν) will determine Vₜ'd.