Partial-wave unitarity constraints on the axigluon mass

We consider two-body scattering processes involving axigluons (the massive color-octet gauge bosons present in all chiral-color models) and heavy quarks, especially QQ QQ (mediated by s- and t-channel axigluons A). Calculating tree-level partial-wave amplitudes aJ for these processes and demanding that aJ <1 so that perturbation theory is valid we find constraints of the form gsMQ<MA. Using collider limits on the top-quark mass we find the lower bound MA>29 GeV if the perturbative expansion for such processes is not to break down which is better than any previous limit derived directly from experiment.