Cross Section and Heavy Quark Composition of Photon+Muon Events Produced in ppbar Collisions

TL;DR

This paper measures the cross section and heavy flavor content of photon+muon events in proton-antiproton collisions, providing experimental data that tests QCD predictions about charm and bottom quark production.

Contribution

First measurement of heavy flavor content in photon+muon events in hadronic collisions, comparing experimental results with QCD predictions.

Findings

Measured cross section of 46.8 pb for photon transverse momentum 12-40 GeV/c.

Found a charm to bottom production ratio of 2.4, consistent with QCD models.

Observed the measured cross section to be below theoretical predictions by two standard deviations.

Abstract

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 ppbar collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to Compton scattering process charm+gluon -> charm+photon, 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 prediction. 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.