Search for resonances decaying into photon pairs in 139 fb$^{-1}$ of $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector

The collaboration
CERN-EP-2020-248, 2021.

Abstract (data abstract)
CERN-LHC. Search for resonances decay into photon pairs in 139 fb^{-1} of proton-proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector between 2015--2018. The fiducial region for the combined spin-0/spin-2 resonance search is defined as: - 2 photons - E_T > 0.3 m_gamgam for the photon with leading E_T, and E_T > 0.25 m_gamgam for the photon with sub-leading E_T - |eta_gam| < 2.37 - An isolation requirement using all particles with lifetime greater than 10 ps at the generator level in a cone of Delta_R = 0.4 around the photon direction: E^iso_T< 0.05 E_T + 6 GeV. For the spin-2 resonance search, the acceptance and efficiencies are assumed to be those obtained from MC simulation of KK graviton decays.