Isodoublet color-octet scalar bosons appear in a natural extension of the minimal dynamical symmetry-breaking model triggered by a $t\overline{t}$ condensate, which is geared to yield the top mass in the experimentally expected region. We study the effect of these bosons on the rate for the radiative decay $b\to s\gamma$. It is shown that the standard model branching fraction gets enhanced and the constraints we obtain on the mass of these bosons are in agreement with those obtained from other processes such as $B_d-{\overline{B}}_d$ mixing and the value of the $\epsilon$ parameter. A mass of Å75 GeV or less for the charged bosons is thereby excluded.

• Received 23 September 1993

DOI:https://doi.org/10.1103/PhysRevD.49.4801