Search for narrow scalar $X\rightarrow\gamma\gamma$ in the mass range 65-600 GeV with the ATLAS detector

A search for scalar narrow resonances decaying into two photons in the mass range 65-600 GeV is performed using 20 fb$^{-1}$ of pp collision data collected with the ATLAS detector at $\sqrt{s}$ = 8 TeV at the Large Hadron Collider. The Higgs boson of mass 125.9 GeV is treated as a background. No significant evidence for an additional signal is observed. The result is presented as a model-independent limit at the 95% confidence level on the production cross-section times the branching fraction BR ($X\rightarrow\gamma\gamma$), in a fiducial volume where the reconstruction efficiency is independent of the event topology. The upper limits set extend over a considerably wider mass range than for the limits previously set by the ATLAS and CMS collaborations, which cover only the mass range 110-150 GeV.