The virtual photon absorption cross section differences [σ1/2 - σ3/2] for the proton and neutron have been determined from measurements of polarised cross section asymmetries in deep inelastic scattering of 27.5 GeV longitudinally polarised positrons from polarised 1H and 3He internal gas targets. The data were collected in the region above the nucleon resonances in the kinematic range v< 23.5 GeV and 0.8 GeV2 < Q2 < 12 GeV2. For the proton the contribution to the generalised Gerasimov-Drell-Hearn integral was found to be substantial and must be included for an accurate determination of the full integral. Furthermore the data are consistent with a QCD next-to-leading order fit based on previous deep inelastic scattering data. Therefore higher twist effects do not appear significant.
|Number of pages||8|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Dec 24 1998|
Bibliographical noteFunding Information:
We gratefully acknowledge the DESY management for its support and the staffs at DESY and the collaborating institutions for their significant effort. This work was supported by the Fund for Scientific Research-Flanders (FWO) of Belgium; the Natural Sciences and Engineering Research Council of Canada; the INTAS, HCM and TMR contributions from the European Community; the German Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF), the Deutscher Akademischer Austauschdienst (DAAD); the Italian Istituto Nazionale di Fisica Nucleare (INFN); Monbusho, JSPS, and Toray Science Foundation of Japan; the Dutch Stichting voor Fundamenteel Onderzoek der Materie (FOM); the UK Particle Physics and Astronomy Research Council; and the US Department of Energy and National Science Foundation.
ASJC Scopus subject areas
- Nuclear and High Energy Physics