New cross sections for the reaction ep→epη are reported for total center of mass energy W=1.5–1.86GeV and invariant momentum transfer Q2=0.25–1.5(GeV/c)2. This large kinematic range allows extraction of important new information about response functions, photocouplings, and ηN coupling strengths of baryon resonances. Newly observed structure at W∼1.65GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance.
Physical Review Letters
Thompson, R.; Biselli, Angela; and CLAS Collaboration, "The ep→e′pη Reaction at and above the S11(1535) Baryon Resonance" (2001). Physics Faculty Publications. 108.
R. Thompson et al. [CLAS Collaboration], "The ep→e′pη Reaction at and above the S11(1535) Baryon Resonance" Physical Review Letters 86.17 (2001) DOI: 10.1103/PhysRevLett.86.1702