Charged hadron lepto-production off unpolarized protons and deuterons at HERMES

Abstract

The HERMES collaboration has measured charge-separated pion and kaon multiplicities in semi-inclusive deep-inelastic scattering using a 27.6 GeV electron or positron beam scattering off a hydrogen or deuterium target. The results are presented as functions of the Bjorken variable xB, the negative squared four-momentum transfer Q2, a hadron fractional energy z and the hadron's transverse momentum. These data will be very useful to understand the quark-fragmentation process in deep-inelastic hadron electro-production and will serve as crucial input in the understanding of charge and flavour separated fragmentation functions. Furthermore, it provides important information on the transverse-momentum dependence of hadron production.