The branching ratio $R_b$ in the littlest Higgs model

Abstract

In the context of the littlest Higgs(LH) model, we study the contributions of the new particles to the branching ratio $R_b$. We find that the contributions mainly dependent on the free parameters $f$, $c^{\prime }$ and $x_L$. The precision measurement value of $R_b$ gives severe constraints on these free parameters.

Comments: Latex files, 25 pages and 11 figures. To be published in Nucl. Phys.B