QCD exotics versus a Standard Model Higgs

Abstract

The present collider data put severe constraints on any type of new strongly-interacting particle coupling to the Higgs boson. We analyze the phenomenological limits on exotic quarks belonging to non-triplet SU(3)_C representations and their implications on Higgs searches. The discovery of the Standard Model Higgs, in the experimentally allowed mass range, would exclude the presence of exotic quarks coupling to it. Thus, such QCD particles could only exist provided that their masses do not originate in the SM Higgs mechanism.

Comments: 11 pages, 8 figures. One appendix added and references updated. Results unchanged and more relevant after the recent discovery of a Higgs-like particle. Matches version to be published in Phys. Rev. D