Analysis of tbW and ttZ couplings from CLEO and LEP/SLC data

Abstract

We update the constraints on anomalous dimension four $\tbw$ and $\ttz$ couplings by using CLEO $b \ra s \gamma$ and LEP/SLC precision $Z$-pole data. It is found that the data imposes very stringent bounds on them. Moreover, the $2 \sigma$ pull from SM predictions of $A_{LR}$(hadrons), $A_b$ and $A_{FB}$(b) have little chance of being explained by the strongly constrained anomalous couplings.