First Measurement of the Gerasimov-Drell-Hearn Sum Rule for 1H from 0.7 to 1.8 GeV at ELSA

H Dutz; K Helbing; J Krimmer; T Speckner; G Zeitler; J Ahrens; S Altieri; J R M Annand; G Anton; H-J Arends; R Beck; A Bock; C Bradtke; A Braghieri; W v  Drachenfels; F Frommberger; M Godo; S Goertz; P Grabmayr; S Hasegawa; K Hansen; J Harmsen; E Heid; W Hillert; H Holvoet; N Horikawa; T Iwata; L Van Hoorebeke; N d'Hose; P Jennewein; B Kiel; F Klein; R Kondratiev; M Lang; B Lannoy; R Leukel; V Lisin; D Menze; W Meyer; T Michel; J Naumann; A Panzeri; P Pedroni; T Pinelli; I Preobrajenski; E Radtke; G Reicherz; C Rohlof; T Rostomyan; M Sauer; B Schoch; M Schumacher; G Tamas; A Thomas; R van de Vyver; W Weihofen; F Zapadtka; GDH Collaboration

doi:10.1103/PhysRevLett.91.192001

First Measurement of the Gerasimov-Drell-Hearn Sum Rule for 1H from 0.7 to 1.8 GeV at ELSA

Phys Rev Lett. 2003 Nov 7;91(19):192001. doi: 10.1103/PhysRevLett.91.192001. Epub 2003 Nov 4.

Affiliation

¹ Physikalisches Institut, Universität Bonn, D-53115 Bonn, Germany.

PMID: 14611575
DOI: 10.1103/PhysRevLett.91.192001

Abstract

To verify the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the first time experimentally, we measured the helicity dependent total photoabsorption cross section with circularly polarized real photons and longitudinally polarized nucleons in the photon energy range 0.68-1.82 GeV with the tagged photon facility at ELSA. The experiment was carried out with a 4pi detection system, a circularly polarized tagged photon beam, and a frozen spin polarized proton target. The contribution to the GDH sum rule in this photon energy range is [49.9+/-2.4(stat)+/-2.2(syst)] microb.