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Unitarity cusp in proton Compton scattering

Journal Article · · Physical Review, C (Nuclear Physics); (United States)
;  [1]
  1. Saskatchewan Accelerator Laboratory, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 0W0 (Canada)
Recent proton Compton scattering data from Saskatoon spanning the pion threshold region are shown to reflect the presence of a unitarity cusp (Wigner cusp), long predicted but never before observed. The analysis is based on a formulation of the Compton cross section employing convenient semiphenomenological expressions for the four dominant multipole amplitudes, designed to respect the low energy theorem and other constraints. Unitarity anomalies have now been detected in both the elastic (Compton) and inelastic ([pi][sup 0][ital p]) channels of the [gamma]+[ital p] reaction.
OSTI ID:
6140201
Journal Information:
Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 48:4; ISSN 0556-2813; ISSN PRVCAN
Country of Publication:
United States
Language:
English