Końcowe stany hadronowe w głęboko nieelastycznym rozpraszaniu elektron-proton w obszarze małych wartości x-Bjorkena na akceleratorze HERA

Abstract

The electron-proton collider HERA with centre of mass system energy of about 300 GeV has extended the available kinematic regime in deep inelastic scattering to low values of Bjorken-x (10−5−10−3) and made possible studies of the QCD dynamics in this region. The processes in which partons carry a very small fraction of the proton momentum may show deviations from the standard DGLAP dynamics and it is believed that their correct description is provided by the BFKL evolution formalism. Low x phenomena have been initially studied with the HERA data on F2 structure function and later with more exclusive measurements of the hadronic final state. In this report recent results of these studies and especially dedicated measurements of jets and π◦ mesons, produced close to the proton remnant, are reviewed. The data are used to discriminate between QCD models with different parton evolution approximations. For completeness, measurements at e+e− and p¯p colliders sensitive to the BFKL dynamics are also described.