A search for scalar particles decaying via narrow resonances into two photons in the mass range 65–600 GeV is performed using $20.3{\mathrm{fb}}^{-1}$ of $\sqrt{s}=8\mathrm{TeV}$ $pp$ collision data collected with the ATLAS detector at the Large Hadron Collider. The recently discovered Higgs boson is treated as a background. No significant evidence for an additional signal is observed. The results are presented as limits at the 95% confidence level on the production cross section of a scalar boson times branching ratio into two photons, in a fiducial volume where the reconstruction efficiency is approximately independent of the event topology. The upper limits set extend over a considerably wider mass range than previous searches.

• Received 25 July 2014

DOI:https://doi.org/10.1103/PhysRevLett.113.171801

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Published by the American Physical Society