Journal of High Energy Physics

, 2010:52

BK*+, Kℓ+ decays in a family non-universal Z′ model


DOI: 10.1007/JHEP04(2010)052

Cite this article as:
Chang, Q., Li, XQ. & Yang, YD. J. High Energ. Phys. (2010) 2010: 52. doi:10.1007/JHEP04(2010)052


Motivated by the observed forward-backward asymmetry in BK*+ decay, we perform a detailed analysis of this decay mode within a family non-universal Z′ model. With the related coupling \( Z' - \bar sb \) constrained by \( {B_s} - {\bar B_s} \) mixing, BπK and BXsμ+μ decays, we look for further constraint on the couplings Z′ − μ+μ from \( {A_{FB}}{\left( {B \to {K^*}{\mu^{+} }{\mu^{-} }} \right)_{0{\text{Ge}}{{\text{V}}^2} \leqslant {q^2} \leqslant 2{\text{Ge}}{{\text{V}}^2}}} \) and get numerically \( B_{\mu \mu }^{L,R} \sim \mathcal{O}\left( {{{10}^{ - 2}}} \right) \). Moreover, we find that the relations \( B_{\mu \mu }^L < B_{\mu \mu }^R \) and \( B_{\mu \mu }^L + B_{\mu \mu }^R < 0 \), with a small negative phase ϕsL, are crucial to moderate the discrepancy for AFB(BK*μ+μ) between the SM prediction and the experimental data. Numerically, comparing with the SM prediction, we find that \( {A_{FB}}{\left( {B \to {K^*}{\mu^{+} }{\mu^{-} }} \right)_{0{\text{Ge}}{{\text{V}}^2} \leqslant {q^2} \leqslant 2{\text{Ge}}{{\text{V}}^2}}} \) could be enhanced about 80% and 50% by Z′ contribution at most in scenarios S1 and S2, corresponding to the two fitted results of ϕs by UTfit collaboration, respectively. However, the results are still about 1.5σ lower than the experimental measurement.


Rare DecaysBeyond Standard ModelB-Physics

Copyright information

© SISSA, Trieste, Italy 2010

Authors and Affiliations

  1. 1.Department of PhysicsHenan Normal UniversityXinxiang, HenanP. R. China
  2. 2.Institute of Particle PhysicsHuazhong Normal UniversityWuhan, HubeiP. R. China
  3. 3.Institut für Theoretische Physik ERWTH Aachen UniversityAachenGermany
  4. 4.Key Laboratory of Quark & Lepton Physics, Ministry of EducationHuazhong Normal UniversityWuhan, HubeiP. R. China