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Title Spin Asymmetries and Helicity Amplitudes on Photo-Production from Polarized Neutrons
Authors Andrew Sandorfi
JLAB number JLAB-PHY-18-2677
LANL number (None)
Other number DOE/OR/23177-4399
Document Type(s) (Meeting) 
Associated with EIC: No
Supported by Jefferson Lab LDRD Funding: No
Funding Source: Nuclear Physics (NP)
 

Meeting
Invited Talk Paper compiled for NStar 2017

Journal
Compiled for Few Body Systems
Volume 60
Issue 1
Page(s) 10
Refereed


Proceedings
Proceedings of NSTAR 2017. (Few Body Syst. 60 (2019) no.1)
Edited By R. Gothe, Y. Ilieva, V. Mokeev, E. Santopinto, S. Strauch
Springer (2019) Refereed
Page(s) 10
Publication Abstract: Pseudoscalar meson photoproduction experiments lead the search for an expanded $N^*$ spectroscopy that is required by lattice solutions of QCD. Extensive data have been collected with proton targets that can potentially over-determine the production amplitude and allow a search for weak resonances. In contrast, data on photoproduction from neutrons is drastically limited. Both are needed since the $\gamma p N^*$ and $\gamma n N^*$ photo-couplings to {\small {\it I}=$1/2$} states are different and provide complementary information on the mechanisms for resonance excitation. The main subtleties in experiments with an effective polarized neutron target are reviewed. The considerable impact of new polarization data on multipole analyses are discussed, using the example of recent $\pi^- p$ measurements of the beam-target helicity asymmetry ($E$) from polarized $H\!D$ in CLAS at Jefferson Lab. New partial wave analyses incorporating these data have found significant changes in helicity amplitudes of some established resonances, and signatures of weak resonances that previously were observed only in hyperon decay channels.
Experiment Numbers: E06-101
Group: Hall B
Document: pdf
DOI: https://doi.org/10.1007/s00601-018-1478-4
Accepted Manuscript:
Supporting Documents:
Supporting Datasets: