One-loop decays ${A^0} \to ZZ, Z\gamma, \gamma\gamma$ within the 2HDM and its search at the LHC

Abstract

The general two-higgs doublet model (2HDM) contains a rich spectrum of neutral and charged Higgs bosons, whose detection would be a clear signal of new physics. When the Higgs potential is CP-conserving, the spectrum includes a pseudoscalar mass eigenstate $A^{0}$, which does not couple to vector bosons at tree-level. However, fermionic loops (top and bottom mainly) induce the coupling $AVV'$ (with $V,V'=\gamma, Z$) at higher orders. We evaluate the amplitude for the decays ${A^0} \to ZZ, Z\gamma, \gamma\gamma$, including a generic fermionic loop contribution, and present results on the branching ratios for 2HDM-I,II and III. Current LHC searches on heavy Higgs bosons are used as an estimate to constrain the allowed mass range for $A^0$.