Off-Shell CHY Amplitudes and Feynman Graphs
arXiv:1910.12791 · doi:10.1007/JHEP04(2020)141
Abstract
A polynomial form is established for the off-shell CHY scattering equations proposed by Lam and Yao. Re-expressing this in terms of independent Mandelstam invariants provides a new expression for the polynomial scattering equations, immediately valid off shell, which makes it evident that they yield the off-shell amplitudes given by massless Feynman graphs. A CHY expression for individual Feynman graphs, valid even off shell, is established through a recurrence relation.
19 pages, clarification of equations (1.13), (3.7), (3.9), added Comments, corrected reference