We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon + muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV 𝑝⁢¯𝑝 collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to the Compton scattering process 𝑐⁢→𝑔⁡𝑐⁢𝛾, with the final-state charm quark producing a muon. The cross section for events with a photon transverse momentum between 12 and 40 GeV/𝑐 is measured to be 46.8 ±6.3 ±7.5 pb, which is two standard deviations below the most recent theoretical calculation. A significant fraction of the events in the sample contain a final-state bottom quark. The ratio of charm to bottom production is measured to be 2.4 ±1.2, in good agreement with QCD models.

This work was supported by the U.S. Department of Energy and National Science Foundation, the Italian Istituto Nazionale di Fisica Nucleare, the Ministry of Science, Culture and Education of Japan, and the Alfred P. Sloan Foundation.

CDF Collaboration: et al.

Peer reviewed