Investigation of the Conjectured Nucleon Deformation at Low Momentum Transfer
Abstract
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(E3/21+/M3/21+)=(-2.3±0.3stat+syst±0.6model)% and Re(S3/21+/M3/21+)=(-6.1±0.2stat+syst±0.5model)% for M3/21+=(41.4±0.3stat+syst±0.4model)(10-3/mπ+). The derived amplitudes give credence to the conjecture of deformation in hadrons favoring, at low Q2, the dominance of mesonic effects.
- Publication:
-
Physical Review Letters
- Pub Date:
- January 2005
- DOI:
- 10.1103/PhysRevLett.94.022003
- arXiv:
- arXiv:nucl-ex/0408003
- Bibcode:
- 2005PhRvL..94b2003S
- Keywords:
-
- 13.60.Le;
- 13.40.Gp;
- 14.20.Gk;
- Meson production;
- Electromagnetic form factors;
- Baryon resonances with S=0;
- Nuclear Experiment
- E-Print:
- 4 pages, 1figure