Search for SUSY in Events with a Photon, a Lepton, and Missing Transverse Energy Using Full Run2 Dataset at 13 TeV

We present the results of a search for new physics in events with a photon, an electron or muon, and large missing transverse momentum( \(\text {p}_{\text {T}}^{\text {miss}}\) ). The study is based on a sample of proton-proton collisions at \(\mathrm {\sqrt{s}} = 13\) TeV corresponding to an integrated luminosity of 137 \(\text {fb}^{-1}\) collected with the CMS detector in 2016–2018. Many models of new physics predict events with jets and significant \(\text {p}_{\text {T}}^{\text {miss}}\) in addition to electroweak gauge bosons. Notably, models of supersymmetry (SUSY) with gauge-mediated supersymmetry breaking naturally yield events with photons in the final state. Searches for events with both a photon and a lepton are not only sensitive probes of these models, but they also have the potential to help characterize the branching fractions of new particles. We interpret the results of our search in the context of simplified SUSY models.