Abstract
First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction γ→p→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-. L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, Jülich-Bonn, and SAID groups.
Original language | English (US) |
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Pages (from-to) | 53-58 |
Number of pages | 6 |
Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
Volume | 750 |
DOIs | |
State | Published - Nov 12 2015 |
Keywords
- Baryon spectroscopy
- FROST experiment
- Pion photoproduction
- Polarization observables
ASJC Scopus subject areas
- Nuclear and High Energy Physics