摘要
Using the topcolor-assisted technicolor models,we give the anomalous Wtb couplings arising from the exchange of the new gauge bosons(ETC gauge boson,colorons and Z')and calculate their contributions to the b→sγbranching ratio.We find that the contributions mainly come from colorons and the recent measured value of the b→sγbranching ratio gives a strong constraint on the masses of colorons.
基金
Supported by the National Natural Science Foundation of China under Grant No.19905004
the Excellent Youth Foundation of Henan Scientific Commit tee and Foundation of Henan Educational Commit tee.