Search for New Resonances Decaying to Pairs of Merged Diphotons in Proton-Proton Collisions at $\sqrt{s}$ = 13 TeV

A search is presented for an extended Higgs sector with two new particles, 𝑋 and 𝜙, in the process 𝑋 → 𝜙⁢𝜙 → (𝛾⁢𝛾)⁢(𝛾⁢𝛾). Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at $\sqrt{s}$ = 13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 138 fb⁻¹. No evidence of such resonances is seen. Upper limits are set on the production cross section for 𝑚_𝑋 between 300 and 3000 GeV and 𝑚_𝜙/𝑚_𝑋 between 0.5% and 2.5%, representing the most sensitive search in this channel.. Authors: Hayrapetyan, A. [Yerevan Physics Institute]; Tumasyan, A. [Yerevan Physics Institute] (ORCID:0009000006846742); Adam, W. [Institut für Hochenergiephysik] (ORCID:0000000190994341); Andrejkovic, J. W. [Institut für Hochenergiephysik]; Bergauer, T. [Institut für Hochenergiephysik] (ORCID:0000000257860293). DOE Contract: 89243024CSC000002; SC0010005. Subjects: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; extensions of Higgs sector; hadron colliders; hypothetical scalars; photons