  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.
