Author: Richard Cross(University of Wisconsin-Madison)
Title: Structure Functions, the Gluon Density, and PQCD Tests
Abstract: Measurements of the proton structure function F_2 for0.11 < Q^2 < 20000 GeV^2 and 1.2 X 10^-5 < x < 0.65from ZEUS 1994-1997 measurements are presented.From ZEUS 1994 and 1995 F_2 data the slopes d(F_2)/d(ln Q^2) at fixed xand d(ln F_2)/d(ln(1/x)) for x < 0.01 at fixed Q^2 are derived.For the latter E665 data are also used. The transition region in Q^2is explored using the simplest non-perturbative models and NLO QCD.The data at very low Q^2 <= 0.65 GeV^2 are describedsuccessfully by Regge theory. From a NLO QCD fit to ZEUS data the gluon density in theproton is extracted in the range 3 X 10^-5 < x < 0.7.Data from NMC and BCDMS constrain the fit at large x.Assuming the NLO QCD description to be valid down to Q^2 of 1 GeV^2,it is found that the qqbar sea distribution is stillrising at small x and the lowest Q^2 values whereas the gluondistribution is strongly suppressed. Preliminary ZEUS 1996-1997 $F_2$ measurements are also presented.
Comments: 7 pages, LateXReport-no: Subj-class: High Energy Physics - ExperimentJournal-ref: