We report new precise H(e, e′p)-π0 measurements at the Δ(1232) resonance at Q2 = 0.127 (GeV/c)2 obtained at the MIT-Bates out-of-plane scattering facility which are particularly sensitive to the transverse electric amplitude (E2) of the γ*N → Δ transition. The new data have been analyzed together with those of earlier measurements to yield precise quadrupole to dipole amplitude ratios: Re(E 1+3/2/M1+3/2) = (-2.3 ± 0.3stat+syst ± 0.6model)% and Re(S 1+3/2/M1+3/2) = (-6.1 ± 0.2stat+syst ± 0.5model)% for M1+ 3/2 = (41.4 ± 0.3stat+syst ± 0.4 model)(10-3/mπ+). The derived amplitudes give credence to the conjecture of deformation in hadrons favoring, at low Q2, the dominance of mesonic effects.
ASJC Scopus subject areas
- Physics and Astronomy(all)