Measurement of the associatedγ+μ±production cross section inpp¯collisions ats=1.8TeV

We present the first measurement of associated direct photon$+$ muonproduction in hadronic collisions, from a sample of 1.8 TeV $p\ overline{p}$ collisions recorded with the Collider Detectorat Fermilab. Quantum chromodynamics(QCD) predicts that these events are primarily from the Compton scatteringprocess $c\stackrel{\ensuremath{\rightarrow}}{g}c\ensuremath{\gamma},$ with the final state charm quarkproducing a muon. Hence this measurement is sensitive to the charm quarkcontent of the proton. The measured cross section of $29\ifmmode\pm\else\textpm\fi{}9$ pb is compared to a leading-order QCD parton showermodel as well as a next-to-leading-order QCD calculation.