Simultaneous Photoproduction of {eta} and {pi}{sup 0} Mesons on the Proton

• Published in: Physical review letters Vol. 100; no. 5
• Main Authors: Ajaka, J., Assafiri, Y., Bouchigny, S., Didelez, J. P., Fichen, L., Guidal, M., Hourany, E., Kunne, R., Bartalini, O., D'Angelo, A., Di Salvo, R., Fantini, A., Moricciani, D., Schaerf, C., Bellini, V., Giusa, A., Randieri, C., Russo, G., Sperduto, M., Sutera, M.
• Format: Journal Article
• Language: English
• Published: United States 08-02-2008
• Subjects: ASYMMETRY; CHIRALITY; DELTA-1700 BARYONS; DIFFERENTIAL CROSS SECTIONS; ETA MESONS; EXCITATION; GEV RANGE 01-10; INTERMEDIATE STATE; LAGRANGIAN FUNCTION; MESON-BARYON INTERACTIONS; PARTICLE DECAY; PHOTOPRODUCTION; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PIONS NEUTRAL; PROTONS; RESONANCE
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PHYSREVLETT.100.052003

The analysis of the {gamma}p{yields}{eta}{pi}{sup 0}p reaction has been performed using data from the GRAAL experiment. The total and differential cross sections and the beam asymmetry have been obtained from threshold up to 1.5 GeV of beam energy. The two resonances S{sub 11}(1535) and {delta}(1700) are expected to be excited in the intermediate states of this reaction. The results are used to test predictions based on the assumption that both resonances are dynamically generated from the meson-baryon interaction provided by chiral Lagrangians. The term involving the {delta}(1700) excitation, followed by the decay into {eta}{delta}(1232), is found to be dominant.