Search for Flavor-Changing Neutral Current Interactions of the Top Quark and Higgs Boson in Final States with Two Photons in Proton-Proton Collisions at $\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}

Proton-proton interactions resulting in final states with two photons are studied in a search for the signature of flavor-changing neutral current interactions of top quarks ( t ) and Higgs bosons ( H ). The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb-1 . No significant excess above the background prediction is observed. Upper limits on the branching fractions ( B ) of the top quark decaying to a Higgs boson and an up ( u ) or charm ( c ) quark are derived through a binned fit to the diphoton invariant mass spectrum. The observed (expected) 95% confidence level upper limits are found to be 0.019% (0.031%) for B ( t → Hu ) and 0.073% (0.051%) for B ( t → Hc ) . These are the strictest upper limits yet determined.