Like sign top quark pair production at linear colliders

In the general two Higgs doublet model with flavor changing neutral Higgs couplings, neutral Higgs bosons may decay dominantly via tc or tc final states. At the linear collider, e+e− → h0A0 or H0A0 production processes may result in bbtc, W+W−tc or ttcc (or ttcc) final states. The process γγ → h0, A0 → tc is also promising, but e+e− → (h0, H0)Z0 → tcZ0 is relatively suppressed. The possibility of observing like sign lepton pairs, usually the hallmark for neutral meson mixing, is quite interesting since T0 mesons do not even form.