Title

Beam-Target Helicity Asymmetry for γ→ n→→ π− p in the N* Resonance Region

Document Type

Article

Publication Date

2017

Abstract

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π−+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN∗ resonance photocouplings.

Comments

Copyright 2017 American Physical Society

A link to full text has been provided for authorized subscribers.

Publication Title

Physical review letters

Published Citation

Ho, D., P. Peng, C. Bass, P. Collins, A. D’Angelo, A. Deur, J. Fleming, Biselli A. et al [CLAS Collaboration]. "Beam-Target Helicity Asymmetry for γ→ n→→ π− p in the N* Resonance Region." Physical review letters 118, no. 24 (2017). https://doi.org/10.1103/PhysRevLett.118.242002

DOI

10.1103/PhysRevLett.118.242002

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