Speaker
Description
On-shell amplitudes reveal the independent interactions of effective field theory (EFT), complementing redundant Lagrangian descriptions. This review follows the on-shell approach from kinematics, factorization, recursion, and soft constraints to nonredundant massless and massive amplitude bases. We discuss harmonic analysis, Young tableaux, and massive spinor-helicity methods, emphasizing minimal-dimension bases, on-shell Higgsing, the relation between Standard Model EFT and Higgs EFT, and static–recoil power counting. We then review matching, renormalization group evolution, and partial-wave selection rules, including the regulated and evanescent information required beyond four-dimensional physical bases. Applications to colliders, compact-object dynamics and radiation, positivity, and numerical bootstrap bounds connect local amplitudes to observables and ultraviolet consistency. Throughout, we distinguish basis construction, regulated calculations, and physical projections while clarifying their connections, providing a systematic route from independent EFT interactions to phenomenology and ultraviolet constraints.
