Helicity Asymmetry in gamma p -> pi+ n with FROST
The main objective of the FROST experiment at Jefferson Lab is the study of baryon resonances. The polarization observable E for the reaction gamma p to pi+n has been measured as part of this program. A circularly polarized tagged photon beam with energies from 0.35 to 2.35 GeV was incident on a longitudinally polarized frozen-spin butanol target. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer. Preliminary polarization data agree fairly well with present SAID and MAID partial-wave analyses at low photon energies. In most of the covered energy range, however, significant deviations are observed. These discrepancies underline the crucial importance of polarization observables to further constrain these analyses.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1038729
- Report Number(s):
- JLAB-PHY-11-1358; DOE/OR/23177-1731; arXiv:1108.3050; TRN: US1201976
- Journal Information:
- AIP Conf. Proc., Vol. 1432; Conference: NSTAR 11, 17-20 May 2011, Newport News, VA
- Country of Publication:
- United States
- Language:
- English
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