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

Abstract

The differential cross-section for the exclusive process p(e, e0p) has been measured at Q2 5.7 and 7.0 (GeV/c)2, which represents the highest momentum transfer measurement of this to date, significantly higher than the previous highest at Q2 3.6 (GeV/c)2. Data was taken for centre-of-mass energies from threshold to 1.8 GeV, encompassing the S11(1535) resonance, which dominates the p channel. The total cross section is obtained, from which is extracted the helicity-conserving transition amplitude A1/2, for the production of the S11(1535) resonance. This quantity appears to begin scaling as Q−3, a predicted signal of the dominance of perturbative QCD, within the Q2 range of this measurement. No currently available theoretical predictions can account for the behaviour of this quantity over the full measured range of Q2.