Semi-inclusive deeply inelastic scattering at small q_T

Measurement of the distribution of hadronic energy in the final state in deeply inelastic electron scattering at DESY HERA can provide a good test of our understanding of perturbative QCD. For this purpose, we consider the energy distribution function, which can be computed without needing final state parton fragmentation functions. We compute this distribution function for finite transverse momentum q_T at order α_s, and use the results to sum the perturbation series to obtain a result valid for both large and small values of transverse momentum.