New CP phase of $B_s-\bar B_s$ mixing on ${\rm T}$ violation in $B_{d(s)}\to K^*(\phi) \ell^{+} \ell^{-}$

TL;DR

This paper explores a new CP-violating phase in B_s mixing caused by exotic quarks, linking it to observable effects in B decays and potential enhancements in rare decay rates, challenging the CKM paradigm.

Contribution

It proposes a model with exotic quarks inducing a new CP phase via Z-mediated FCNC, connecting B_s mixing, rare B decays, and CP violation observables.

Findings

New CP phase can be detected through T violation in B decays.

Branching ratio of B_s→μ+μ− can be significantly enhanced.

Model links B_s mixing with rare decay processes.

Abstract

A large CP-violating phase uncovered recently by CDF and D$\O$ collaborations in the time-dependent CP asymmetry (CPA) of the $B_s\to J/\Psi \phi$ decay clearly indicates that a non-Cabibbo-Kobayashi-Maskawa (CKM) phase has to be brought into the $b\to s$ transition. We find that the model with $SU(2)_L$ singlet exotic quarks can not only provide the new phase induced from the Z-mediated flavor changing neutral current (FCNC) at tree level, but also strongly relate the $B_s-\bar B_s$ mixing, $B_q\to V_q \ell^{+} \ell^{-}$ ($V_{d[s]}=K^*[\phi])$ and $B_s\to \mu^{+} \mu^{-}$ together. In particular, we show that the new CP phase can be unambiguously exposed by the large statistical significances of $T$ violating observables in $B_q\to V_q \ell^{+} \ell^{-}$, while the branching ratio of $B_s\to \mu^{+} \mu^{-}$ can be enhanced to be $O(10^{-8})$.