On large p{sub T} direct {gamma}{close_quote}s, {pi}{sup 0}{close_quote}s, parton k{sub T}, and the gluon distribution

Journal Article · Tue Apr 01 04:00:00 EST 1997 · AIP Conference Proceedings

OSTI ID:624817

Zielinski, M ^[1]

---

1. University of Rochester, Rochester New York14627 (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{lt}p{sub T}{lt}12GeV/c with central rapidities have been measured for 530 and 800GeV/c proton beams and a 515GeV/c {pi}{sup {minus}} 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. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 624817
• Report Number(s): CONF-970463--
• 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

66 PHYSICS
BERYLLIUM 9 TARGET
COPPER
DIFFERENTIAL CROSS SECTIONS
GEV RANGE 100-1000
GLUONS
HYDROGEN 1 TARGET
INCLUSIVE INTERACTIONS
PARTICLE PRODUCTION
PARTICLE RAPIDITY
PHOTONS
PION MINUS REACTIONS
PIONS NEUTRAL
PROTON REACTIONS