Physics Results from HERA

摘要

We present recent data on inclusive and diffractive scattering in deep-inelastic electron-proton reactions at HERA and review the analysis of these data in terms of parton distribution functions. While the main part of the deep-inelastic scattering cross section is well understood in terms of the partonic structure of the proton, the diffractive exchange, being a sizeble fraction of the total cross section, is still under intensive discussion. The extraction of the partonic nature of diffractive exchange is based on the factorization property of QCD, and reveals a clear dominace of gluonic exchange. A direct measurement of the gluon structure of the proton can be achieved by lowering the center-of-mass energy for HERA. These data, combined with the corresponding data from the high energy running, will allow a model-free extraction of the longitudinal structure function, both in inclusive and diffractive scattering, and thus allow for a direct measurement of the gluon distributions in both processes.