# First measurement of the polarization observable E in the View the MathML sourcep→(γ→,π+)n reaction up to 2.25 GeV

Abstract : First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $\vec \gamma \vec p \to \pi^+n$, 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, J\"ulich, and SAID groups.
Type de document :
Article dans une revue
Physics Letters B, Elsevier, 2015, 750, pp.53-58. 〈10.1016/j.physletb.2015.08.053〉
Domaine :

http://hal.in2p3.fr/in2p3-01158154
Contributeur : Sophie Heurteau <>
Soumis le : vendredi 29 mai 2015 - 17:07:01
Dernière modification le : mercredi 31 janvier 2018 - 12:13:02

### Citation

S. Strauch, W. J. Briscoe, M. Döring, E. Klempt, V. A. Nikonov, et al.. First measurement of the polarization observable E in the View the MathML sourcep→(γ→,π+)n reaction up to 2.25 GeV. Physics Letters B, Elsevier, 2015, 750, pp.53-58. 〈10.1016/j.physletb.2015.08.053〉. 〈in2p3-01158154〉

### Métriques

Consultations de la notice