First Measurement of the Polarization Observable E in the p⃗ (γ⃗ ,π+)n Reaction up to 2.25 GeVстатья
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Дата последнего поиска статьи во внешних источниках: 26 декабря 2015 г.
Аннотация:First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E , for the reaction View the MathML source, 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.