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Title: Measurement of the doubly-polarized He 3 ( γ , n ) p p reaction at 16.5 MeV and its implications for the GDH sum rule

We report new measurements of the double-polarized photodisintegration of 3He at an incident photon energy of 16.5 MeV, carried out at the High Intensity γ-ray Source (HIγS) facility located at Triangle Universities Nuclear Laboratory (TUNL). The spin-dependent double-differential cross sections and the contribution from the three-body channel to the Gerasimov–Drell–Hearn (GDH) integrand were extracted and compared with the state-of-the-art three-body calculations. The calculations, which include the Coulomb interaction and are in good agreement with the results of previous measurements at 12.8 and 14.7 MeV, deviate from the new cross section results at 16.5 MeV. Lastly, the GDH integrand was found to be about one standard deviation larger than the maximum value predicted by the theories.
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  1. Triangle Univ. Nuclear Lab., Durham, NC (United States); Duke Univ., Durham, NC (United States)
  2. Triangle Univ. Nuclear Lab., Durham, NC (United States); Duke Univ., Durham, NC (United States); North Carolina Central Univ., Durham, NC (United States)
  3. College of William and Mary, Williamsburg, VA (United States)
  4. Vilnius Univ., Vilnius (Lithuania)
  5. Centro de Fisica Nuclear da Univ. de Lisboa, Lisboa (Portugal)
  6. Jagiellonian Univ., Krakow (Poland)
  7. Triangle Univ. Nuclear Lab., Durham, NC (United States); Univ. of North Carolina, Chapel Hill, NC (United States)
  8. Leibniz Univ. Hannover, Hannover (Germany)
  9. George Washington Univ., Washington, DC (United States)
Publication Date:
Grant/Contract Number:
FG02-03ER41231; FG02-03ER41-231; FG02-03ER41-033; FG02-03ER41-041; DEC-2013/10/M/ST2/00420
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 750; Journal Issue: C; Journal ID: ISSN 0370-2693
Research Org:
Duke Univ., Durham, NC (United States)
Sponsoring Org:
Country of Publication:
United States
GDH sum rule; polarized 3He; photoabsorption; polarization observables
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1241895