Like Sign Top Pair Production at LHC

Having a mass comparable to the weak scale, the top quark may have a sizable flavor changing couplings to Higgs bosons. We show that such couplings can be probed at the LHC through the parton subprocess $c(\bar c)g \to t (\bar t)A^0$, where the pseudoscalar $A^0$ subsequently decays into $t \bar c$ or ${\bar t} c$, giving rise to the intriguing final state of like sign top quark pairs. We also discuss major backgrounds to the above signal, in particular the QCD-Weak process $q\bar q' \to W^+(W^-) t \bar t$. The issue of background reduction is briefly discussed.