How to extract the P{sub 33}(1232) resonance contributions from the amplitudes M{sub 1{sup +}}{sup 3/2},E{sub 1{sup +}}{sup 3/2},S{sub 1{sup +}}{sup 3/2} of pion electroproduction on nucleons
Within the dispersion relation approach, solutions of integral equations for the multipoles M{sub 1{sup +}}{sup 3/2},E{sub 1{sup +}}{sup 3/2},S{sub 1{sup +}}{sup 3/2} are found at 0 < Q{sup 2} < 3 GeV{sup 2}. These solutions should be used as input for the resonance and nonresonance contributions in the analyses of pion electroproduction data in the P{sub 33}(1232) resonance region. It is shown that the traditional identification of the amplitude M{sub 1{sup +}}{sup 3/2} (as well of the amplitudes E{sub 1{sup +}}{sup 3/2},S{sub 1{sup +}}{sup 3/2}) with the P{sub 33}(1232) resonance contribution is not right; there is a contribution in these amplitudes which has a nonresonance nature and is produced by rescattering effects in the diagrams corresponding to the nucleon and pion poles. This contribution is reproduced by the dispersion relations. Taking into account nonresonance contributions in the amplitudes M{sub 1{sup +}}{sup 3/2},E{sub 1{sup +}}{sup 3/2}, the helicity amplitudes A{sub p}{sup 1/2}, A{sub p}{sup 3/2} and the ratio E2/M1 for the {gamma}N {r_arrow} P{sub 33}(1232) transition are extracted from experiment at Q{sup 2}=0. They are in good agreement with quark model predictions.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 756472
- Report Number(s):
- DOE/ER/40150-1566; JLAB-THY-97-31; hep-ph/9708238; TRN: US0003073
- Journal Information:
- Phys.Rev. D57 (1998) 2727-2735, Vol. D, Issue 57; Other Information: Submitted to Phys.Rev. D57 (1998) 2727-2735; PBD: 1 Aug 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
P{sub 33}(1232) resonance contribution to the amplitudes M{sub 1+}{sup 3/2},E{sub 1+}{sup 3/2},S{sub 1+}{sup 3/2} from an analysis of the p(e,e{sup {prime}}p){pi}{sup 0} data at Q{sup 2}=2.8, 3.2, and 4;(GeV/c){sup 2} within the dispersion relation approach
The P{sub 33}(1232) resonance contribution into the amplitudes M{sub 1+}{sup 3/2}, E{sub 1+}{sup 3/2}, S{sub 1+}{sup 3/2} from an analysis of the p(e,e{prime}p){pi}{sup 0} data at Q{sup 2} = 2.8, 3.2, and 4 (GeV/c){sup 2} within dispersion relation approach