Low Energy Anomaly Processes in the Baryon Sector

林育中(Y. C. Lin)

Chinese Journal of Physics

29卷5期（1991 / 10 / 01）

497 - 504

英文

We construct an anomaly Lagrangian involvingbaryons, mesons and photons in the Skyrme model. The most simple process in this Lagrangian is the neutral pion photoproduction on nucleon. The value of electric dipole amplitude E0+ is calculated and compared with the experimental data. At the pion production threshold we obtain E0+^(anomaly) = 2.99 X 10^(-3)fm = 2.12 X 10^(-3)/mπ+. This value together with the low energy theorem prediction E0+^(L.E.T.) = -2.4 X 10^(-3)/mπ+ gives E0+ = -0.28 X 10^(-3)/mπ+, which is in good agreement with the measured value of E0+ = -0.5 ± 0.3 X 10^(-3)/mπ+. This may reconcile the longstanding difference between theory and experiment. Other anomaly processes such as the Compton scattering γP→γP and πP→π^0πP are also discussed.