Document Type

Article

Publication Date

2015

DOI

10.1016/j.physletb.2015.08.053

Publication Title

Physics Letters B

Volume

750

Pages

53-58

Abstract

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction ɣp→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, Jfilich-Bonn, and SAID groups.

Comments

This is an open access article under the CC BY license.

(https://creativecommons.org/licenses/by/4.0/)

Original Publication Citation

Strauch, S., Briscoe, W. J., Doring, M., Klempt, E., Nikonov, V. A., Pasyuk, E., . . . Collaboration, C. (2015). First measurement of the polarization observable E in the p, π+) in reaction up to 2.25 GeV. Physics Letters B, 750, 53-58. doi: 10.1016/j.physletb.2015.08.053

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