The production cross section times decay branching ratios for $W+\gamma$
and $Z/DY+\gamma$ have been measured in $\sqrt{s}=1.8$ TeV $\bar{p}p$
collisions using muon and electron data samples obtained during the 1992-1993
and 1994-1995 collider runs at the Fermilab Tevatron with the CDF detector
corresponding to a total integrated luminosity of 110 pb$^{-1}$.  
For photons with transverse energy $E^{\gamma}_{T} > 7.0$ GeV, 
pseudorapidity in the central or plug region ($\mid \eta_{l} \mid < 2.4$)
and a lepton-photon angular separation $\Delta R_{l\gamma} > 0.7$, we
observed 122(213) muon(electron) $W\gamma$ candidates and 36(43)
muon(electron) $Z/DY\gamma$ candidates.  We observe a total of 335 muon
plus electron $W+\gamma$ and 79 muon plus electron $Z/DY+\gamma$ candidates,
whereas the standard model expectation is $264.6\pm18.2$ $W+\gamma$ events
and $74.2\pm4.2$ $Z/DY+\gamma$ events.  The combined electron plus muon
channel results correspond to $\sigma \cdot B (W+\gamma) = 19.8\pm1.7$ pb and
$\sigma \cdot B (Z/DY+\gamma) = 5.5\pm0.8$ pb.  The next-to-leading-order
standard model predictions are $\sigma \cdot B (W+\gamma) = 14.8$ pb
and $\sigma \cdot B (Z/DY+\gamma) = 5.8$ pb.  For $W+\gamma$, this
corresponds to a $\sim35\%$ excess relative to the standard model prediction.


Posted to /cdf/pub/thesis/cdf5627_V+gamma_Physics.ps
    http://www-cdf.fnal.gov/thesis/cdf5627_V+gamma_Physics.ps

Posted by leonard@cdfsga.fnal.gov