The SAGEX review on scattering amplitudes Chapter 11: Soft Theorems and Celestial Amplitudes

TASI Lectures on Scattering Amplitudes

Calculation of the Scattering Amplitudes

It is well known that the high order calculations of the observables within the perturbation theory has the serious difficulties (especially, if we take into account the polarization effects). Method of the direct calculation of amplitudes simplifies these calculations essentially. There is an even number (2N) of fermions in initial and final state for any reaction with Dirac particles. Therefo...

Scattering amplitudes and AdS/CFT

Scattering amplitudes in the maximally supersymmetric N = 4 gauge theory are known to possess some remarkable features. The reasons for this are not completely understood, but some possible candidates are: the integrability properties of the theory, the existence of a gravitational dual and the existence of a twistor space description. I will not try to give a detailed description of the N = 4 ...

Factorization constraints for soft anomalous dimensions in QCD scattering amplitudes

We study the factorization of soft and collinear singularities in dimensionallyregularized fixed-angle scattering amplitudes in massless gauge theories. Our factorization is based on replacing the hard massless partons by light-like Wilson lines, and defining gauge-invariant jet and soft functions in dimensional regularization. In this scheme the factorized amplitude admits a powerful symmetry:...

Tree Scattering Amplitudes *

The spin-4/3 fractional superstring is characterized by a chiral algebra involving a spin-4/3 current on the world-sheet in addition to the energy-momentum tensor. These currents generate physical state conditions on the fractional superstring Fock space. Scattering amplitudes of these physical states are described which satisfy both spurious state decoupling and cyclic symmetry (duality). Exam...