On large p{sub T} direct {gamma}'s, {pi}{sup 0}'s, parton k{sub T}, and the gluon distribution

Journal Article · Sun Apr 20 04:00:00 EDT 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.53617· OSTI ID:21167568

Zielinski, Marek ^[1]

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1. University of Rochester, Rochester New York 14627 (United States)

Predictions of perturbative QCD (pQCD) for the inclusive production of direct photons and mesons at high p{sub T} have been tested using new high-statistics measurements from Fermilab experiment E706. Inclusive {pi}{sup 0} and direct-{gamma} cross sections in the kinematic range 3.5<p{sub T}<12 GeV/c with central rapidities have been measured for 530 and 800 GeV/c proton beams and a 515 GeV/c {pi}{sup -} beam incident on a Be target. Current Next-to-Leading Log (NLL) pQCD calculations fail to describe the data for usual choices of scales. Other aspects of the data indicate the presence of a substantial initial state parton transverse momentum (k{sub T}) in the hard scattering. Incorporating a kinematic model of k{sub T} effects improves the agreement between the calculations and the observed cross sections. Gluon distributions are extracted from Deep Inelastic Scattering (DIS), Drell-Yan (DY), and our direct photon data using fitting procedures similar to those used by the CTEQ collaboration; calculations using these new pdf fits yield jet cross sections consistent with CDF and D0 measurements.

• OSTI ID: 21167568
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 407; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CROSS SECTIONS
DEEP INELASTIC SCATTERING
DRELL MODEL
FERMILAB
FERMILAB COLLIDER DETECTOR
GEV RANGE
GLUONS
JET MODEL
PARTICLE IDENTIFICATION
PARTICLE PRODUCTION
PARTICLE RAPIDITY
PHOTONS
PIONS MINUS
PIONS NEUTRAL
PROTON BEAMS
PROTON REACTIONS
QUANTUM CHROMODYNAMICS
STATISTICS
TRANSVERSE MOMENTUM