The European Physical Journal C

, 71:1775

BK1+ decays in a family non-universal Z′ model

Regular Article - Theoretical Physics

DOI: 10.1140/epjc/s10052-011-1775-2

Cite this article as:
Li, Y., Hua, J. & Yang, KC. Eur. Phys. J. C (2011) 71: 1775. doi:10.1140/epjc/s10052-011-1775-2


The implications of the family non-universal Z′ model in the BK1(1270,1400)+(=e ,μ ,τ) decays are explored, where the mass eigenstates K1(1270, 1400) are the mixtures of 1P1 and 3P1 states with the mixing angle θ. In this work, considering the Z′ boson and setting the mixing angle θ=(−34±13), we analyze the branching ratio, the dilepton invariant mass spectrum, the normalized forward–backward asymmetry and lepton polarization asymmetries of each decay mode. We find that all observables of BK1(1270)μ+μ are sensitive to the Z′ contribution. Moreover, the observables of BK1(1400)μ+μ have a relatively strong θ-dependence; thus, the Z′ contribution will be buried by the uncertainty of the mixing angle θ. Furthermore, the zero crossing position in the FBA spectrum of BK1(1270)μ+μ at low dilepton mass will move to the positive direction with Z′ contribution. For the tau modes, the effects of Z′ are not remarkable due to the small phase space. These results could be tested in the running LHC-b experiment and Super-B factory.

Copyright information

© Springer-Verlag / Società Italiana di Fisica 2011

Authors and Affiliations

  1. 1.Department of PhysicsYantai UniversityYantaiChina
  2. 2.Department of PhysicsChung Yuan Christian UniversityTaiwanRepublic of China