K. Hartman

Direct photon production at high p-transverse in pi- Be and p Be collisions at 500-GeV/c

We report new measurements of inclusive direct photon production at high transverse momenta (pT) for π - and p interactions on Be at 500 Gev/r. The yields as a function of pT and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions

Evidence for parton

Inclusive pizero and direct-photon cross sections in the kinematic range 3.5 < pT < 12 GeV/c with central rapidities are presented for 530 and 800 GeV/c proton beams and a 515 GeV/c pi- beam incident on beryllium targets. Current Next-to-Leading-Order perturbative QCD calculations fail to adequately describe the data for conventional choices of scales. Kinematic distributions from these hard scattering events provide evidence that the interacting partons carry significant initial-state parton transverse momentum (kT). Incorporating these kT effects phenomenologically greatly improves the agreement between calculations and the measured cross sections.

k_{T}

We are studying production of χc states in 530 GeV/c π− interactions with several targets. χc mesons are observed in the mode (χ→J/ψ+γ). Only photons that converted to e+e− pairs are used in the reconstruction of the χc mesons. Preliminary analysis shows that the fraction of observed J/ψs coming from χc radiative decays is 0.44±0.09±0.08, and that the relative production rate of χc1 to χc2 is 1.3±0.6.

effects in high

We report on the production of J/psi mesons in 530 and 800 GeV/c proton - Be collisions in the Feynman-x range 0.0 < xf < 0.6. The J/psi mesons were detected via decays into opposite sign muon pairs. Differential distributions for J/psi production have been measured as functions of xf, pT^2, and cosine of the Gottfried-Jackson decay angle. These distributions are compared with results on J/psi production obtained in 515 GeV/c pion - Be collisions, measured by the same experiment, as well as with results from other experiments using incident protons.

p_{T}

We report on the production of J/psi mesons in 530 and 800 GeV/c proton - Be collisions in the Feynman-x range 0.0 < xf < 0.6. The J/psi mesons were detected via decays into opposite sign muon pairs. Differential distributions for J/psi production have been measured as functions of xf, pT^2, and cosine of the Gottfried-Jackson decay angle. These distributions are compared with results on J/psi production obtained in 515 GeV/c pion - Be collisions, measured by the same experiment, as well as with results from other experiments using incident protons.

particle production

Inclusive pizero and direct-photon cross sections in the kinematic range 3.5 < pT < 12 GeV/c with central rapidities are presented for 530 and 800 GeV/c proton beams and a 515 GeV/c pi- beam incident on beryllium targets. Current Next-to-Leading-Order perturbative QCD calculations fail to adequately describe the data for conventional choices of scales. Kinematic distributions from these hard scattering events provide evidence that the interacting partons carry significant initial-state parton transverse momentum (kT). Incorporating these kT effects phenomenologically greatly improves the agreement between calculations and the measured cross sections.

Hadroproduction of χc states in 530 GeV/c π− interactions with nuclear targets

We report new measurements of inclusive direct photon production at high transverse momenta (pT) for π - and p interactions on Be at 500 Gev/r. The yields as a function of pT and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions

Production ofJ/ψmesons inpBecollisions at 530 and800GeV/c

We report new measurements of inclusive direct photon production at high transverse momenta (pT) for π - and p interactions on Be at 500 Gev/r. The yields as a function of pT and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions

Production of

We report new measurements of inclusive direct photon production at high transverse momenta (pT) for π - and p interactions on Be at 500 Gev/r. The yields as a function of pT and rapidity (y) are in good agreement with expectations from next-to-leading-log QCD calculations employing recently extracted quark and gluon structure functions

J/\psi

We present new measurements of {pi}{sup 0} production at high transverse momenta ({ital p}{sub {ital T}}) for {pi}{sup {minus}} and {ital p} interactions on Be and Cu targets at 500 GeV/{ital c}. The observed dependence of the yields as a function of {ital p}{sub {ital T}} and rapidity ({ital y}) is compared with expectations from leading-log QCD over a kinematic range in which the inclusive cross sections fall by more than 4 orders of magnitude.