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arXiv · hep-ph/9508338

The $Z \to b \bar b$ Excess and Top Decay

Ernest Ma·Daniel Ng
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Abstract

The apparent excess of $Z \rightarrow b \bar b$ events at LEP may be an indication of new physics beyond the standard model. However, in either the two-Higgs-doublet model or the minimal supersymmetric standard model, any explanation would lead to an important new decay mode of the top quark and suppresses the $t \rightarrow W b$ branching fraction, which goes against what has been observed at the Tevatron. In the two-Higgs-doublet model, the branching fraction of $Z \rightarrow b \bar b$ + a light boson which decays predominantly into $b \bar b$ would be at least of order 10$^{-4}$.

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Ernest Ma, Daniel Ng. 1995-08-21. The $Z \to b \bar b$ Excess and Top Decay. https://doi.org/10.1103/physrevd.53.255

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