EXTRACTION OF THE GLUON DENSITY OF THE PROTON AT X RID B-9165-2008 RID C-5889-2009 RID A-4818-2008 RID C-1693-2008

The gluon momentum density xg(x, Q(2)) of the proton was extracted at Q(2) = 20 GeV2 for small values of x between 4 x 10(-4) and 10(-2) from the scaling violations of the proton structure function F-2 measured recently by ZEUS in deep inelastic neutral current ep scattering at HERA. The extraction was performed in two ways. Firstly, using a global NLO fit to the ZEUS data on F-2 at low x constrained by measurements from NMC at larger x; and secondly using published approximate methods for the solution of the GLAP QCD evolution equations. Consistent results are obtained. A substantial increase of the gluon density is found at small x in comparison with the NMC result obtained at larger values of x

JET PRODUCTION IN HIGH Q(2) DEEP-INELASTIC EP SCATTERING AT HERA RID B-9165-2008 RID C-5889-2009 RID A-4818-2008 RID C-1693-2008

Two-jet production in deep-inelastic electron-proton scattering has been studied for 160 < Q(2) < 1280 GeV2 0.01 < x < 0.1 and 0.04 < y < 0.95 with the ZEUS detector at HERA. The kinematic properties of the jets and the jet production rates are presented. The partonic scaling variables of the two-jet system and the rate of two-jet production are compared to perturbative next-to-leading order QCD calculations