CMS-PAS-SMP-20-005

CMS-PAS-SMP-20-005
W $^{\pm}\gamma$ differential cross sections and effective field theory constraints at $\sqrt{s}=$ 13 TeV
CMS Collaboration
March 2021

Abstract: Differential cross section measurements of W $^{\pm}\gamma$ production in proton-proton collisions at $\sqrt{s} =$ 13 TeV are presented. The data set used in this study is collected with the CMS detector at the CERN LHC and corresponds to an integrated luminosity of 137 fb $^{-1}$ . Candidate events containing an electron or muon, a photon, and missing transverse momentum are selected. The measurements are compared to standard model predictions computed at next-to-leading order and next-to-next-to-leading order in perturbative quantum chromodynamics. Constraints on the presence of heavy new physics affecting the WW $\gamma$ vertex are determined within an effective field theory framework, focusing on the $\mathcal{O}_{3W}$ operator. A simultaneous measurement of the photon transverse momentum and the azimuthal angle of the charged lepton in a special reference frame is performed. This two-dimensional approach yields sensitivity to the interference between the standard model and $\mathcal{O}_{3W}$ that is enhanced by up to a factor of ten compared to using the transverse momentum alone.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to PRD. The superseded preliminary plots can be found here.

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