The Low Energy Theorem and Resonance Contributions in Threshold Pion-Photoproductions of Nucleons

Zhen-Ping Li

Chinese Journal of Physics

32卷6S期（1994 / 12 / 01）

1381 - 1391

英文

The low energy theorem of threshold pion-photoproductioll is shown to be fully recovered in the quark model. The leading contributions to the isospin amplitucles at O(μ^2) are from the transition between the P-wave baryons and the nucleon, and from the charge radius of the nucleon. The leading contribution from the P-wave baryons only affects neutral pion production, and improves the agreement with data significantly. The transition between the resonance P33(1232) and the nucleon only gives an order μ^3 correction to A(-).