https://doi.org/10.1140/epja/i2016-16333-5
Regular Article - Experimental Physics
Photon asymmetry measurements of 
for 
320-650 MeV
1
SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
2
Institut für Kernphysik, University of Mainz, D-55099, Mainz, Germany
3
Kent State University, 44242, Kent, OH, USA
4
Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, D-53115, Bonn, Germany
5
INFN Sezione di Pavia, I-27100, Pavia, Italy
6
SUPA, School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
7
The George Washington University, 20052, Washington, DC, USA
8
University of California Los Angeles, 90095-1547, Los Angeles, CA, USA
9
Lebedev Physical Institute, 119991, Moscow, Russia
10
Institut für Physik, University of Basel, CH-4056, Basel, Switzerland
11
Mount Allison University, E4L3B5, Sackville, New Brunswick, Canada
12
Institute for Nuclear Research, 125047, Moscow, Russia
13
Rudjer Boskovic Institute, HR-10000, Zagreb, Croatia
14
University of Regina, SK S4S 0A2, Regina, Canada
15
Joint Institute for Nuclear Research, 141980, Dubna, Russia
16
Department of Astronomy and Physics, Saint Marys University, Halifax, Canada
17
University of Massachusetts Amherst, 01003, Amherst, MA, USA
* e-mail: s.gardner.1@research.gla.ac.uk
Received:
28
June
2016
Accepted:
8
October
2016
Published online:
17
November
2016
High-statistics measurements of the photon asymmetry 
for the 
reaction have been made in the center-of-mass energy range 
MeV. The data were measured with the MAMI A2 real photon beam and Crystal Ball/TAPS detector systems in Mainz, Germany. The results 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, 
, 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 
and 
resonances.
© The Author(s), 2016
