\( B_s^0 - \overline B_s^0 \) mixing in a family non-universal Z′ model revisited


DOI: 10.1007/JHEP05(2012)049

Cite this article as:
Li, XQ., Li, YM., Lu, GR. et al. J. High Energ. Phys. (2012) 2012: 49. doi:10.1007/JHEP05(2012)049


Motivated by the very recent measurements performed at the LHCb and the Tevatron of the \( B_s^0 - \overline B_s^0 \) mixing, in this paper we revisit it in a family non-universal Z′ model, to check if a simultaneous explanation for all the mixing observables, especially for the like-sign dimuon charge asymmetry observed by the D0 collaboration, could be made in such a specific model. In the first scenario where the Z′ boson contributes only to the off-diagonal element \( M_{{{12}}}^s \), it is found that, once the combined constraints from ΔMs, ϕs and ΔΓs are imposed, the model could not explain the measured flavour-specific CP asymmetry \( a_{{fs}}^s \), at least within its 1σ ranges. In the second scenario where the NP contributes also to the absorptive part \( \Gamma_{{{12}}}^s \) via tree-level Z′-induced b\( c\overline c s \) operators, we find that, with the constraints from ΔMs, ϕs and the indirect CP asymmetry in \( {{\overline B }_d} \)J/ψKS taken into account, the present measured 1σ experimental ranges for \( a_{{fs}}^s \) could not be reproduced too. Thus, such a specific Z′ model with our specific assumptions could not simultaneously reconcile all the present data on \( B_s^0 - \overline B_s^0 \) mixing. Future improved measurements from the LHCb and the proposed superB experiments, especially of the flavour-specific CP asymmetries, are expected to shed light on the issue.


Beyond Standard Model B-Physics CP violation 

Copyright information

© SISSA, Trieste, Italy 2012

Authors and Affiliations

  • Xin-Qiang Li
    • 1
    • 2
  • Yan-Min Li
    • 1
  • Gong-Ru Lu
    • 1
  • Fang Su
    • 3
  1. 1.Department of PhysicsHenan Normal UniversityXinxiangChina
  2. 2.IFIC, Universitat de València-CSICValènciaSpain
  3. 3.Institute of Particle PhysicsHuazhong Normal UniversityWuhanChina