Leptophobic Z′ gauge boson appears naturally in many grand unified theories, such as flipped SU (5) or string-inspired E6 models. This elusive particle easily escapes the direct/indirect detections because it does not couple to charged leptons. However, it can generate flavor changing neutral current at tree level. In this Letter, we show that the recently measured mass difference, Δ ms, in the Bs0 - over(B, ̄)s0 system improves the previous bound of flavor changing effective coupling by about one order of magnitude, i.e. irrespective of its phase, | UsbZ′ | ≤ 0.036 for MZ= 700 = GeV, and | UsbZ′ | ≤ 0.051 for MZ =1 TeV.
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 2006 Oct 5|
Bibliographical noteFunding Information:
We thank Sechul Oh for careful reading of the manuscript and his valuable comments. The work of C.S.K. was supported in part by CHEP-SRC Program, in part by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) No. KRF-2005-070-C00030. The work of S.B. was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) No. KRF-2005-070-C00030. J.H.J. was supported by BK21 Program of Korean Government.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics