出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We compute the Compton scattering off the nucleons in the framework of manifestly covariant
baryon chiral perturbation theory (BχPT). The results for observables differ substantially from
the corresponding calculations in heavy-baryon chiral perturbation theory (HBχPT), most appreciably
in the forward kinematics. We verify that the covariant p3 result fulfills the forward-
Compton-scattering sum rules. We also explore the effect of the Δ(1232) resonance at order
p4/Δ , with Δ ≈ 300 MeV, the resonance excitation energy. We find that the substantial effect of
the Δ-excitation on the nucleon polarizabilities can naturally be accommodated in the manifestly
covariant calculation.
