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Title: Photon asymmetry measurements of $$\overrightarrow{\gamma}p \rightarrow \pi^{0} p$$ γ → p → π 0 p for $$E_{\gamma}=$$ E γ = 320-650 MeV

High-statistics measurements of the photon asymmetry Σ for the $$\overrightarrow{\gamma}p \rightarrow \pi^{0} p$$ reaction have been made in the center-of-mass energy range W = 1214–1450 MeV. The data were measured with the MAMI A2 real photon beam and Crystal Ball/TAPS detector systems in Mainz, Germany. The resulting measurements significantly improve the existing world data and are shown to be in good agreement with previous measurements, and with the MAID, SAID, and Bonn-Gatchina predictions. We have also combined the photon asymmetry results with recent cross-section measurements from Mainz to calculate the profile functions, $$\check{Σ}$$ (= σ 0Σ), and perform a moment analysis. Comparison with calculations from the Bonn-Gatchina model shows that the precision of the data is good enough to further constrain the higher partial waves, and there is an indication of interference between the very small F-waves and the N(1520)3/2 - and N(1535)1/2 - resonances.
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Publication Date:
Grant/Contract Number:
SC0014133; SAPPJ-2015-00023
Type:
Accepted Manuscript
Journal Name:
European Physical Journal. A
Additional Journal Information:
Journal Volume: 52; Journal Issue: 11; Journal ID: ISSN 1434-6001
Publisher:
Springer
Research Org:
George Washington Univ., Washington, DC (United States)
Sponsoring Org:
USDOE; Science and Technology Facilities Council (STFC) (United Kingdom); German Research Foundation (DFG); European Union (EU); Swiss National Science Foundation (SNSF); National Science Foundation (NSF); Natural Sciences and Engineering Research Council of Canada (NSERC)
Contributing Orgs:
The A2 Collaboration at MAMI
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1425737