One-loop analytical expressions for $γγ\rightarrow φ_iφ_j$ in Higgs Extensions of the Standard Models and its applications

Abstract: General one-loop formulas for loop-induced processes $\gamma \gamma \rightarrow \phi_i\phi_j$ with $\phi_i\phi_j = hh,~hH,~HH$ are presented in the paper. Analytic expressions evaluated in this work are valid for a class of Higgs Extensions of the Standard Models, e.g. Inert Doublet Higgs Models, Two Higgs Doublet Models, Zee-Babu Models as well as Triplet Higgs Models, etc. Analytic expressions for one-loop form factors are written in terms of the basic scalar one-loop two-, three- and four-point functions following the output format of both the packages~{\tt LoopTools} and {\tt Collier}. Physical results can be hence evaluated numerically by using one of the mentioned packages. Analytic results are tested by several checks such as the ultraviolet finiteness, infrared finiteness of the one-loop amplitudes. Furthermore, the amplitudes also obey the ward identity due to the on-shell initial photons. This identity is also verified numerically in this works. In the applications, we present the phenomenological results for Zee-Babu model as a typical example in this report. Production cross-section for the processes $\gamma \gamma\rightarrow hh$ are scanned over the parameter space of the Zee-Babu Models.