Electroproduction of η mesons in the S11(1535) resonance region at high momentum transfer

The differential cross section for the process p(e,e'p)η has been measured at Q2~5.7 and 7.0(GeV/c)2 for center-of-mass energies from threshold to 1.8 GeV, encompassing the S11(1535) resonance, which dominates the channel. This is the highest momentum-transfer measurement of this exclusive process to date. The helicity-conserving transition amplitude A1/2, for the production of the S11(1535) resonance, is extracted from the data. Within the limited Q2 now measured, this quantity appears to begin scaling as Q-3-a predicted, but not definitive, signal of the dominance of perturbative QCD at Q2~5 (GeV/c)2. © 2009 The American Physical Society.