When the Higgs meets the top: Search for t→ch0 at the LHC

The newly discovered “Higgs” boson h0, being lighter than the top quark t, opens up new probes for flavor and mass generation. In the general two Higgs doublet model, new ct, cc and tt Yukawa couplings could modify h0 properties. If t→ch0 occurs at the percent level, the observed ZZ⁎ and γγ signal events may have accompanying cbW activity coming from tt¯ feeddown. We suggest that t→ch0 can be searched for via h0→ZZ⁎, γγ, WW⁎ and bb¯, perhaps even τ+τ− modes in tt¯ events. Existing data might be able to reveal some clues for t→ch0 signature, or push the branching ratio B(t→ch0) down to below the percent level.