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arXiv · hep-ph/9612376

Supersymmetry, Supergravity and R_b revisited in the light of LEP 2

J. Ellis·J. Lopez·D. Nanopoulos
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Abstract

A previous study of supersymmetric models has indicated that they are unlikely to make a large contribution to R_b. We revisit this analysis, taking into account the improved lower limits on sparticle masses provided recently by LEP 2 and the Tevatron, finding that a generic supersymmetric model cannot contribute more than about one-and-a-half current experimental standard deviations to R_b. We then specialize this analysis to minimal supergravity models with universal high-energy boundary conditions, and find a much more stringent upper bound R^{susy}_b < 0.0003. We discuss in detail why such models can only attain values of R^{susy}_b that are considerably smaller even than those obtainable in more general supersymmetric models.

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J. Ellis, J. Lopez, D. Nanopoulos. 1996-12-16. Supersymmetry, Supergravity and R_b revisited in the light of LEP 2. https://doi.org/10.1016/s0370-2693(97)00156-1

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