The t-channel contribution to the difference of electromagnetic polarizabilities of the nucleon, (α−β)t, can be quantitatively understood in terms of a σ-meson pole in the complex t-plane of the invariant scattering amplitude A1(s, t) with properties of the σ meson as given by the quark-level Nambu–Jona-Lasinio model (NJL). Equivalently, this quantity may be understood in terms of a cut in the ...

Applications of effective field theory to nucleon-nucleon scattering, quarkonia decay and production and B meson decay are discussed. Some unresolved issues are considered.

Applications of effective field theory to nucleon-nucleon scattering, quarkonia decay and production and B meson decay are discussed. Some unresolved issues are considered.