Multiplicities of charged pions and kaons from semi-inclusive deep-inelastic scattering by the proton and the deuteron

Multiplicities in semi-inclusive deep-inelastic scatteringare presented for each charge state of pi(+/-) and K-+/- mesons. The data were collected by the HERMES experimentat the HERA storage ringusing 27.6 GeV electron and positron beams incident on a hydrogen or deuterium gas target. The results are presented as a function of the kinematic quantities x(B), Q(2), z, and P-h perpendicular to. They represent a unique data set for identified hadrons that will significantly enhance our understanding of the fragmentation of quarks into final-state hadrons in deep-inelastic scattering.