A measurement of jet cross sections at low Q"2 and an interpretation of the results in terms of a partonic structure of the virtual photon

Measurements of single inclusive jet cross-sections are presented using deep inelastic scattering data from H1 in the kinematic region 0.65 < Q"2 < 50.0 GeV"2 and 0.3 < y < 0.6. The results are compared to a number of QCD based models. Good agreement is found with models which treat the virtual photon as having both a pointlike coupling to the quarks and antiquarks in the proton and a coupling where the photon first acquires a partonic structure before interacting strongly with the proton. The inclusive dijet cross-sections, measured in the kinematic region 1.6 < Q"2 < 100.0 GeV"2 and 0.1 < y < 0.7 are in agreement with the picture of the virtual photon having a partonic structure in the region where E_T"*"2 >> Q"2. The ratio #sigma#(res)/#sigma#(dir) is also presented and shows the partonic structure of the photon to decrease with increasing photon virtuality. (author)SIGLEAvailable from British Library Document Supply Centre-DSC:DXN045613 / BLDSC - British Library Document Supply CentreGBUnited Kingdo