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DF Geesaman

Publications and source records attributed to DF Geesaman.

At least 19 recordsLinked to original sources
PubMed2000

Evidence for valencelike quark-hadron duality

A newly obtained data sample of inclusive electron-nucleon scattering from both hydrogen and deuterium targets is analyzed. These JLab data span the nucleon resonance region up to four-momentum transfers of 5 (GeV/c)(2). The data are found to follow an average scaling curve. The inclusion of low-momentum transfer data yields a scaling curve resembling deep inelastic neutrino-nucleus scattering data, suggesting a sensitivity to valencelike structure only.

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PubMed2000

Experimental verification of quark-hadron duality

A newly obtained sample of inclusive electron-nucleon scattering data has been analyzed for precision tests of quark-hadron duality. The data are in the nucleon resonance region, and span the range 0. 3<Q2<5.0 (GeV/c)(2). Duality is observed both in limited and extended regions around the prominent resonance enhancements. Higher twist contributions to the F2 structure function are found to be small on average, even in the low Q2 regime of approximately 0.5 (GeV/c)(2). Using duality, an average scaling curve is obtained. In all cases, duality appears to be a nontrivial property of the nucleon structure function.

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PubMed2000

Measurement of differences between J/psi and psi(') suppression in p-A collisions

Measurements of the suppression of the yield per nucleon of J/psi and psi(') production for 800 GeV/ c protons incident on heavy nuclear targets, relative to light nuclear targets, have been made with very broad coverage in x(F) and p(T). The observed suppression is smallest at x(F) values of 0.25 and below, and increases at larger values of x(F). It is also strongest at small p(T). Substantial differences between psi(') and J/psi production are observed for the first time in p-A collisions. The suppression for psi(') production is stronger than that for J/psi for x(F) near zero, but becomes comparable to that for J/psi for x(F)>0.6.

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