Type: Article
Publication Date: 2004-10-21
Citations: 33
DOI: https://doi.org/10.1103/physrevd.70.074008
We present a measurement of the isolated direct photon cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.8\text{ }\text{ }\mathrm{T}\mathrm{e}\mathrm{V}$ and $|\ensuremath{\eta}|<0.9$ using data collected between 1994 and 1995 by the Collider Detector at Fermilab (CDF). The measurement is based on events where the photon converts into an electron-positron pair in the material of the inner detector, resulting in a two track event signature. To remove ${\ensuremath{\pi}}^{0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ and $\ensuremath{\eta}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ events from the data we use a new background subtraction technique which takes advantage of the tracking information available in a photon conversion event. We find that the shape of the cross section as a function of photon ${p}_{T}$ is poorly described by next-to-leading-order QCD predictions, but agrees with previous CDF measurements.