Authors
IFAE-Barcelona
Fermilab
Ray Culbertson (rlc@fnal.gov)
Mario Martinez (mmp@fnal.gov)
Shin Shan Yu (eikoyu@fnal.gov)
Carolina Deluca (cdeluca@fnal.gov)
P.0. Box 500, M.S. 318
Batavia, Illinois 60510
USA
We present preliminary results on inclusive direct photon production in p-pbar collisions at √s = 1.96 TeV using data
collected with the upgraded Collider Detector at Fermilab in Run II corresponding to an integrated
luminosity of 451pb-1. Measurements are performed as a function of the photon transverse momentum for photons with
pT > 30 GeV/c and |&eta|<1.0. Photons are required to be isolated in the calorimeter
(isolation < 2 GeV). The measurements are corrected to the hadron level and compared to NLO pQCD predictions.
The theoretical predictions are not corrected for non-pQCD contributions.
Trigger efficiency curve
Events are collected with a trigger logic that requires at least one isolated photon with pT
above 25 GeV/c.
The trigger efficiency, as determined using Z->ee data, is 100% in
the kinematic range considered in the measurement (shown below).
Signal and Background Separation
Signal and background (dominated by pi0 decays) contributions are determined by-bin-bin from a fit to the calorimeter
isolation distribution in the data, for which photon and background templates are extracted from MC samples. Details for
two bins in pT are presented below.
Photon Fraction
A conservative ~15% systematic uncertainty is included.
The Cross Section Result