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Particles and Fields

Eur. Phys. J. C 20, 553-562 (2001)
DOI: 10.1007/s100520100691

Rb and $R_{\ell}$ in MSSM without R-parity

J.M. Yang

Institute of Theoretical Physics, Academia Sinica, Beijing 100080, P.R. China

(Received: 14 October 1999 / Revised version: 2 May 2001 / Published online: 8 June 2001 -© Springer-Verlag / Società Italiana di Fisica 2001)

We examined $Zb\bar b$ and $Z\ell \bar \ell$ couplings in the minimal supersymmetric model with explicit trilinear R-parity violating interactions. We found that the top quark couplings $\lambda'_{i3k}$ and $\lambda''_{3j3}$ can give sizable contributions through top quark loops. When deriving the bounds from Rb and $R_{\ell}$ data, we also take into account the loop contributions of R-parity conserving interactions. The bounds from $R_{\ell}$ are found to be stronger than those from Rb and serve as the hitherto strongest bounds for some couplings.

© Società Italiana di Fisica, Springer-Verlag 2001