Semi-inclusive hadron production at DESY HERA: The effect of QCD gluon resummation

We present a formalism that improves the applicability of perturbative QCD in the current region of semi-inclusive deep inelastic scattering (DIS). The formalism is based on all-order resummation of large logarithms arising in the perturbative treatment of hadron multiplicities and energy flows in this region. It is shown that the current region of semi-inclusive DIS is similar to the region of small transverse momenta in vector boson production at hadron colliders. We use this resummation formalism to describe transverse energy flows and charged particle multiplicity measured at the DESY electron-proton collider HERA. We find good agreement between our theoretical results and experimental data for the transverse energy flows.