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Electromagnetic couplings of the ChPT Lagrangian from the perturbative chiral quark model

V. E. Lyubovitskij·Th. Gutsche·Amand Faessler·R. Vinh Mau
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Abstract

We apply the perturbative chiral quark model to the study of the low-energy pi-N interaction. Using an effective chiral Lagrangian we reproduce the Weinberg-Tomozawa result for the S-wave pi-N scattering lengths. After inclusion of the photon field we give predictions for the electromagnetic O(p^2) low-energy couplings of the chiral perturbation theory effective Lagrangian that define the electromagnetic mass shifts of nucleons and first-order (e^2) radiative corrections to the pi-N scattering amplitude. Finally, we estimate the leading isospin-breaking correction to the strong energy shift of the pi(-)p atom in the 1s state, which is relevant for the experiment "Pionic Hydrogen" at PSI.

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V. E. Lyubovitskij, Th. Gutsche, Amand Faessler, R. Vinh Mau. 2001-11-09. Electromagnetic couplings of the ChPT Lagrangian from the perturbative chiral quark model. https://doi.org/10.1103/physrevc.65.025202

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