Physics

Mathematics

Mathematical physics

Spinor

Musical

Algorithm

Visual arts

Electroweak interaction

Amplitude

Theoretical physics

Computation

Fermion

Massless particle

Quantum mechanics

Formalism (music)

Covariant transformation

Classical mechanics

Journal of High Energy Physics

A bstract The purely on-shell approach to effective field theories requires the construction of independent contact terms. Employing the little-group-covariant massive-spinor formalism, we present the first systematic derivation of independent four-point contact terms involving massive scalars, spin-1 / 2 fermions, and vectors. Independent three-point amplitudes are also listed for massive particles up to spin-3. We make extensive use of the simple relations between massless and massive amplitudes in this formalism. Our general results are specialized to the (broken-phase) particle content of the electroweak sector of the standard model. The (anti)symmetrization among identical particles is then accounted for. This work opens the way for the on-shell computation of massive four-point amplitudes.

Constructing massive on-shell contact terms