Diquark Higgs bosons at the CERN LHC

Existence of color sextet diquark Higgs fields with TeV masses will indicate a fundamentally different direction for unification than conventional grand unified theories. One class of models where they appear naturally is the supersymmetric SU(2)L×SU(2)R×SU(4)c model embedding the seesaw mechanism for neutrino mass with seesaw scale around 10¹¹ GeV. The diquark Higgs fields in this model couple only to up-type quarks. We discuss phenomenological constraints on these fields and show that they could be detected at LHC via their decay to either $tt$ or single top+jet. We also find that existing Tevatron data gives a lower bound on its mass somewhere in the 400--500 GeV, for reasonable values of its coupling.