2013/03/19 by Jacob L. Bourjaily, Simon Caron-Huot, Bourjaily, Jacob L. +3 · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1303.4734
openalex publication_date 2013/03/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We revisit the familiar construction of one-loop scattering amplitudes via\ngeneralized unitarity in light of the recently understood properties of loop\nintegrands prior to their integration. We show how in any four-dimensional\nquantum field theory, the integrand-level factorization of infrared divergences\nleads to twice as many constraints on integral coefficients than are visible\nfrom the integrated expressions. In the case of planar, maximally\nsupersymmetric Yang-Mills amplitudes, we demonstrate that these constraints are\nboth sufficient and necessary to imply the finiteness and dual-conformal\ninvariance of the ratios of scattering amplitudes. We present a novel\nregularization of the scalar box integrals which makes dual-conformal\ninvariance of finite observables manifest term by term, and describe how this\nprocedure can be generalized to higher loop-orders. Finally, we describe how\nthe familiar scalar boxes at one-loop can be upgraded to `chiral boxes'\nresulting in a manifestly infrared-factorized, box-like expansion for all\none-loop integrands in planar, N=4 super Yang-Mills. Accompanying this note is\na Mathematica package which implements our results, and allows for the\nefficient numerical evaluation of any one-loop amplitude or ratio function.\n