Measurements of the spin-difference cross sections entering the Gerasimov-Drell-Hearn (GDH) sum rule are reviewed. Results on the proton from Mainz and Bonn exceeded the GDH prediction by 22 mu b, requiring as yet unmeasured canceling high-energy components. Recent experiments with frozen-spin HD at BNL reveal a different angular dependence for pi(0) production than what was assumed in Mainz analyses in lieu of direct measurements and integrate to a value that is 18 mu b lower, suggesting a rapid convergence. Results for deuterium over limited energy ranges are consistent with large canceling contributions but differ from existing state of the art calculations.

Sandorfi, A., Hoblit, S., Ardashev, K., Bade, C., Bartalini, O., Blecher, M., et al. (2009). Recent Polarization Experiments and the GDH Sum Rule. In SPIN STRUCTURE AT LONG DISTANCE, WORKSHOP PROCEEDINGS (pp.73-81). MELVILLE-NEW YORK -- USA : American Institute of Physics.

Recent Polarization Experiments and the GDH Sum Rule

BARTALINI, ORIETTA;D'ANGELO, ANNALISA;FANTINI, ALESSIA;SCHAERF, CARLO;
2009-01-01

Abstract

Measurements of the spin-difference cross sections entering the Gerasimov-Drell-Hearn (GDH) sum rule are reviewed. Results on the proton from Mainz and Bonn exceeded the GDH prediction by 22 mu b, requiring as yet unmeasured canceling high-energy components. Recent experiments with frozen-spin HD at BNL reveal a different angular dependence for pi(0) production than what was assumed in Mainz analyses in lieu of direct measurements and integrate to a value that is 18 mu b lower, suggesting a rapid convergence. Results for deuterium over limited energy ranges are consistent with large canceling contributions but differ from existing state of the art calculations.
Spin Structure at Long Distance Workshop
Newport News, VA USA
2009
Rilevanza internazionale
su invito
2009
2009
Settore FIS/04 - FISICA NUCLEARE E SUBNUCLEARE
English
GDH Sum Rule; Polarization; photo-production; MAGNETIC MOMENTS; NUCLEON
Intervento a convegno
Sandorfi, A., Hoblit, S., Ardashev, K., Bade, C., Bartalini, O., Blecher, M., et al. (2009). Recent Polarization Experiments and the GDH Sum Rule. In SPIN STRUCTURE AT LONG DISTANCE, WORKSHOP PROCEEDINGS (pp.73-81). MELVILLE-NEW YORK -- USA : American Institute of Physics.
Sandorfi, A; Hoblit, S; Ardashev, K; Bade, C; Bartalini, O; Blecher, M; Caracappa, A; D'Angelo, A; Null, A; Di Salvo, R; Fantini, A; Gibson, C; Gluckl...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/96801
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