Form Factor and Boundary Contribution of Amplitude

TL;DR

This paper explores the boundary contributions in amplitude calculations using BCFW recursion, relating them to form factors and composite operators in N=4 super-Yang-Mills theory, and computes these form factors via double trace amplitudes.

Contribution

It establishes a connection between boundary contributions and form factors of composite operators in N=4 SYM, enabling their computation through amplitude methods.

Findings

Boundary contributions can be expressed as form factors involving boundary operators.

Leading order boundary operators relate to composite operators in N=4 SYM.

Form factors are computed using double trace amplitude techniques.

Abstract

The boundary contribution of an amplitude in the BCFW recursion relation can be considered as a form factor involving boundary operator and unshifted particles. At the tree-level, we show that by suitable construction of Lagrangian, one can relate the leading order term of boundary operators to some composite operators of N=4 super-Yang-Mills theory, then the computation of form factors is translated to the computation of amplitudes. We compute the form factors of these composite operators through the computation of corresponding double trace amplitudes.