Indirect Constraints on the Triple Gauge Boson Couplings from $Z\to b\bar{b}$ Partial Width: An Update

Abstract

We update the indirect bounds on anomalous triple gauge couplings coming from the non-universal one-loop contributions to the $Z\to b\bar{b}$ width. These bounds, which are independent of the Higgs boson mass, are in agreement with the standard model predictions for the gauge boson self-couplings since the present value of $R_b$ agrees fairly well with the theoretical estimates. Moreover, these indirect constraints on $\Delta g_1^Z$ and $g_5^Z$ are more stringent than the present direct bounds on these quantities, while the indirect limit on ${\lambda }_Z$ is weaker than the available experimental data.

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