Measurement of the W gamma Production Cross Section in Proton-Proton Collisions at root s=13 TeV and Constraints on Effective Field Theory Coefficients

A fiducial cross section for (W\gamma ) production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in (137\text{}\text{}{\mathrm{fb}}^{-1}) of data collected using the CMS detector at the LHC. The (W\to e\nu ) and (\mu \nu ) decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.