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Evidence for a parity doublet Delta(1920)P33 and Delta(1940)D33 from gammap-->ppi;{0}eta
I Horn1, A V Anisovich, G Anton
1Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Germany.
Physical Review Letters
|December 31, 2008
Summary
This study provides evidence for a parity doublet of Delta resonances in the photoproduction of the ppi;{0}eta final state. The Delta(1920)P33 and Delta(1940)D33 resonances significantly contribute to the reaction dynamics.
Area of Science:
- Particle Physics
- Nuclear Physics
- Quantum Chromodynamics
Background:
- Understanding the spectrum of excited nucleon and Delta states is crucial for testing theoretical models of Quantum Chromodynamics.
- The existence of parity doublets in the Delta resonance spectrum has been a long-standing question in hadron spectroscopy.
Purpose of the Study:
- To investigate the presence of a parity doublet of Delta resonances.
- To analyze the photoproduction of the ppi;{0}eta final state to identify these resonances.
- To determine the contributions of specific Delta resonances to the reaction.
Main Methods:
- Analysis of experimental data from the photoproduction of the ppi;{0}eta final state.
- Identification of resonance contributions through partial wave analysis.
- Examination of the total angular momentum J=3/2 states.
Main Results:
- Evidence for a parity doublet of Delta resonances with total angular momentum J=3/2 is reported.
- The Delta(1920)P33 and Delta(1940)D33 resonances are identified as significant contributors to the reaction.
- Observed resonance cascades into Delta(1232)eta, N(1535)pi, and Na0(980) states.
Conclusions:
- The findings support the existence of parity partners in the Delta resonance spectrum.
- The identified Delta resonances play a key role in the ppi;{0}eta photoproduction reaction.
- Further theoretical and experimental work is needed to fully elucidate the properties of these resonances.
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