Scattering amplitudes for all masses and spins

A bstract We introduce a formalism for describing four-dimensional scattering amplitudes particles of any mass and spin. This naturally extends the familiar spinor-helicity massless to one where these variables carry an extra SU (2) little group index massive particles, with spin S transforming as symmetric rank 2 tensors. systematically characterise all possible three particle compatible Poincare symmetry. Unitarity, in form consistent factorization, imposes algebraic conditions that can be used construct four-particle tree amplitudes. also gives us convenient basis which expand terms what called “spinning polynomials”. Many general results quantum field theory follow analysis scattering, ranging from set theories spin-statistics, Weinberg-Witten theorem. find transparent understanding why sufficiently high cannot “elementary”. The Higgs Super-Higgs mechanisms are discovered infrared unification many disparate helicity into smaller number amplitudes, simple this can’t extended Higgsing gravitons. illustrate applications at one-loop, giving few-line computations electron ( g ? 2) well beta function rational QCD. “Off-shell” observables like correlation functions form-factors thought external “probe” spin, so objects — factors correlators, studied common on-shell perspective.