CP phase of nonuniversal $Z'$ on $\sin\phi^{J/\Psi \phi}_s$ and T-odd observables of $\bar B_{q}\to V_{q} \ell^{+} \ell^{-}$

TL;DR

This paper investigates how a nonuniversal $Z'$ model can explain large CP phases observed in $B_s$ decays and predicts significant T-odd and polarization asymmetries in $ar B_q o V_q \, ext{leptons}$ decays, providing testable new physics signals.

Contribution

It introduces a family-dependent $U(1)'$ extension to explain CP violation and analyzes its effects on T-odd observables and polarization asymmetries in $B$ meson decays.

Findings

Large CP phase $ o$ T-odd observables >10% in certain decays

Predicted polarization asymmetries are sensitive to $Z'$ effects

Constraints from current data limit the size of new physics contributions

Abstract

The evidence of a large CP phase has been shown by CDF and D{\O} collaborations in the time-dependent CP asymmetry (CPA) of $B_s\to J/\Psi \phi$ decay, where the nonvanished CPA clearly implies the existence of a non-Kobayashi-Maskawa phase in $b\to s$ transition. We study the new phases originated by the extra family dependent $U(1)'$ model and examine their impact on $\hat{T}$ or CP violating observables in $\bar B_q\to V_q \ell^{+} \ell^{-}$ decays with $V_q=K^* (\phi)$. Adopting the constraints from the current data of $\Delta m_s$ and the branching ratios for $\bar B_s\to \mu^+ \mu^-$ and $\bar B_q\to V_q\ell^+ \ell^-$, we find that $\phi^{J/\Psi\phi}_s=-(0.26\pm 0.22)$ and the T-odd observables of above 10% in the decay chain $\bar B_q\to V_q(\to K\pi [KK]) \ell^+ \ell^-$ can be achieved. In addition, we demonstrate that the longitudinal and transverse polarizations of $K^*$ and the up-down asymmetry of $K$ in the same decay chain are also sensitive to the $Z'$-mediated effects.