Discovery of Charged Higgs through {\gamma}{\gamma} final states

Extending the Higgs sector by an additional $SU(2)_L$ doublet Higgs boson implies the existence of a charged Higgs boson $H^+$. The LHC experiments search for such particle focusing on it decays into leptonic and quark decay final states, namely $\tau \nu$,$cs$ and $tb$. However, if the Higgs sector if further extended, e.g. by a gauge singlet as in the NMSSM, the charged Higgs boson can also decay into a light scalar or pseudoscalar Higgs boson which itself decays further into a two photon final state. We present here scenarios where $H^+$ is produced in top-quark decays with a sizable cross-section such the corresponding signal is well above the Standard Model background at the 13 TeV run of Large Hadron Collider (LHC) with an integrated luminosity 100 fb$^{-1}$.