Nonuniversal Z′ couplings in B decays

We study the impacts of the nonuniversal Z′ model, providing flavor-changing neutral current at tree level, on the branching ratios (BRs), CP asymmetries (CPAs), and polarization fractions of B decays. We find that, for satisfying the current data, the new left- and right-handed couplings have to be included at the same time. The new introduced effective interactions not only could effectively explain the puzzle of small longitudinal polarization in B→K* decays, but also provide a solution to the small CPA of B±→π0K±. We also find that the favorable CPA of B±→π0K± is opposite in sign to the standard model; meanwhile, the CPA of Bd→π0K has to be smaller than -10%. In addition, by using the values of parameters which are constrained by B→πK, we find that the favorable ranges of BRs, CPAs, longitudinal polarizations, and perpendicular transverse polarizations for (B±→ρ±K* ,Bd→ρ K*±) are (17.1±3.9,10.0±2.0)×10- 6, (3±5,21±7)%, (0.66±0.10,0.44±0.08), and (0.14±0.10,0.25±0.09), respectively.