Document Type

Article

Article Version

Publisher's PDF

Publication Date

1-1-2009

Abstract

Semi-inclusive π+ electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range including the complete range of azimuthal angles between hadronic and leptonic planes, ϕ, enabling us to separate the ϕ-dependent terms. Our measurements of the ϕ-independent term of the cross section at low Bjorken x were found to be in fairly good agreement with pQCD calculations. Indeed, the conventional current fragmentation calculation can account for almost all of the observed cross section, even at small π+ momentum. The measured center-of-momentum spectra are in qualitative agreement with high-energy data, which suggests a surprising numerical similarity between the spectator diquark fragmentation in the present reaction and the antiquark fragmentation measured in e+e− collisions. We have observed that the two ϕ-dependent terms of the cross section are small. Within our precision the cos2ϕ term is compatible with zero, except for the low-z region, and the measured cosϕ term is much smaller in magnitude than the sum of the Cahn and Berger effects.

Comments

Copyright American Physical Society Publisher final version available at http://prd.aps.org/pdf/PRD/v80/i3/e032004

Publication Title

Physical Review D

Published Citation

M. Osipenko et al. [CLAS Collaboration],"Measurement of semi-inclusive π+ electroproduction off the proton", Physical Review D 80.3 (2009) DOI: 10.1103/PhysRevD.80.032004

DOI

10.1103/PhysRevD.80.032004

Peer Reviewed

Download

Share

COinS