FIZIKA B 13 (2004)  1, 57 - 64

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JLAB EXPERIMENT 01-006: RESONANCES' SPIN STRUCTURE

OSCAR A. RONDON

Institute of Nuclear and Particle Physics - University of Virginia,
Charlottesville, VA 22901, U.S.A.
E-mail address: or@virginia.edu

Received 26 August 2003;        Accepted 26 April 2004
Online 16 July 2004

Experiment 01-006 (Resonances' Spin Structure) was carried out at Jefferson Lab's Hall C to measure the nucleon spin structure functions in the region of the nucleon resonances. Longitudinally polarized electrons of 5.76 GeV beam energy were incident on solid polarized ammonia and deuterated ammonia (15NH3, 15N2H3) targets. The scattered electrons were detected in the High Momentum Spectrometer parked at a 13.15 angle relative to the beam. The polarized target field was used to align the nucleon spins parallel and perpendicular to the beam helicity to measure the corresponding asymmetries A|| and A^. The measured asymmetries are used to extract in a model-free way the nucleon spin asymmetries A1(W,Q2) and A2(W,Q2), which are functions of the invariant mass of the final system, W, and of the four-momentum transfer, Q2. The measurements extend over 0.8GeV W1.95 GeV and are at an average Q2=1.3 [GeV/c]2. Preliminary results are shown, including the world's first set of data on the perpendicular asymmetry of the proton and the deuteron for this kinematic region.

PACS numbers: 13.88.+e, 21.10.Hw, 13.60.Hb
UDC 539.12

Keywords: nucleon spin, nucleon resonances, polarized electron scattering

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