Observation of WWγ Production and Search for Hγ Production in Proton-Proton Collisions at s=13 TeV

Abstract

The observation of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>W</a:mi><a:mi>W</a:mi><a:mi>γ</a:mi></a:mrow></a:math> production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mn>138</c:mn><c:mtext> </c:mtext><c:mtext> </c:mtext><c:msup><c:mrow><c:mi>fb</c:mi></c:mrow><c:mrow><c:mo>−</c:mo><c:mn>1</c:mn></c:mrow></c:msup></c:mrow></c:math> is presented. The observed (expected) significance is 5.6 (5.1) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>W</e:mi><e:mi>W</e:mi><e:mi>γ</e:mi></e:math> is <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:mn>5.9</g:mn><g:mo>±</g:mo><g:mn>0.8</g:mn><g:mrow><g:mo stretchy="false">(</g:mo><g:mi>stat</g:mi><g:mo stretchy="false">)</g:mo></g:mrow><g:mo>±</g:mo><g:mn>0.8</g:mn><g:mrow><g:mo stretchy="false">(</g:mo><g:mi>syst</g:mi><g:mo stretchy="false">)</g:mo></g:mrow><g:mo>±</g:mo><g:mn>0.7</g:mn><g:mrow><g:mo stretchy="false">(</g:mo><g:mi>modeling</g:mi><g:mo stretchy="false">)</g:mo><g:mtext> </g:mtext><g:mtext> </g:mtext><g:mi>fb</g:mi></g:mrow></g:mrow></g:math>, in agreement with the next-to-leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks. © 2024 CERN, for the CMS Collaboration 2024 CERN