The top threshold effect in the $$\gamma \gamma $$ γγ production at the LHC

Abstract

Abstract We compute the top quark threshold contributions to the $$\gamma \gamma $$ γγ production at the LHC. They appear when the invariant mass of the photon pair, $$M_{\gamma \gamma }$$ Mγγ just exceeds two times the mass of the top quark and induce some feature in the $$M_{\gamma \gamma }$$ Mγγ distribution. We determine the magnitude of this threshold effect and characterize this feature with a simple empirical fitting function to show that it is possible to observe this effect at the LHC in future. We also explore some possible improvements that may enhance its significance.