Search for Dark Matter (DM) Using Monophoton Final State in p-p Collisions Using the CMS Detector at the LHC

We report on the results of new physics searches in a final state containing a photon and missing transverse energy called “monophoton searches” in a p-p collision at \(\sqrt{s}\) =13TeV. The data correspond to an integrated luminosity of 138 \(fb^{-1}\) . In the Standard Model, the only process that results in the genuine signature of a single photon and large MET is Z+ \(\gamma \) production, in which the Z boson decays into a neutrino ( \(\nu \) ) and an antineutrino ( \(\nu ^{'}\) ). The rate of Z+ \(\gamma \) production can be precisely calculated in the SM, and therefore a deviation of the observation from the prediction in this signature is a robust indicator of the physics beyond the standard model. This process, in which the Z boson decays to 2 neutrinos, is an irreducible process, as the signal and background look exactly the same in the detector. In practice, multiple other collision and non-collision processes mimic the signature and thus constitute the additional background to this search. We aim to reduce the contributions from such non-Z+ \(\gamma \) backgrounds and other remaining backgrounds using data-driven techniques and Monte Carlo (MC) simulations Results are interpreted in the context of dark matter using simplified models and large extra dimensions using ADD model.