Implications of Family Nonuniversal $Z^\prime$ Model on B -->K_0^* pi Decays

TL;DR

This paper investigates how a family nonuniversal $Z'$ model influences $B o K_0^* o ext{pi}$ decays, showing that certain scenarios align better with experimental data and can be tested in future experiments.

Contribution

It provides a detailed analysis of the effects of a nonuniversal $Z'$ boson on rare B decays within the QCD factorization framework, comparing two scalar meson scenarios.

Findings

Scenario S2 with Case-II best fits experimental data

$Z'$ contributions can modify branching ratios and CP asymmetries

S2 scenario is more favored even with new physics effects

Abstract

Within the QCD factorization formalism, we study the possible impacts of the nonuniversal $Z^\prime$ model, which provides a flavor-changing neutral current at the tree level, on rare decays $B \to K_0^*\pi$. Under two different scenarios (S1 and S2) for identifying the scalar meson $K_0^*(1430)$, the branching ratios, CP asymmetries, and isospin asymmetries are calculated in both the standard model (SM) and the family nonuniversal $Z^\prime$ model. We find that the branching ratios and CP asymmetries are sensitive to weak annihilation. In the SM, with $\rho_A=1$ and $\phi_A\in[-30^\circ, 30^\circ]$, the branching ratios of S1 (S2) are smaller (larger) than the experimental data. Adding the contribution of the $Z^\prime$ boson in two different cases (Case-I and Case-II), for S1, the branching ratios are still far away from experiment. For S2, in Case-II, the branching ratios become smaller and can accommodate the data; in Case-I, although the center values are enhanced, they can also explain the data with large uncertainties. Similar conclusions are also reached for CP asymmetries. Our results indicate that S2 is more favored than S1, even after considering new physics effects. Moreover, if there exists a nonuniversal $Z^\prime$ boson, Case-II is preferred. All results can be tested in the LHC-b experiment and forthcoming super-B factory.