An Automated Implementation of On-Shell Methods for One-Loop Amplitudes
Abstract
We present the first results from BlackHat, an automated C++ program for calculating one-loop amplitudes. The program implements the unitarity method and on-shell recursion to construct amplitudes. As input to the calculation, it uses compact analytic formulae for tree amplitudes for four-dimensional helicity states. The program performs all related computations numerically. We make use of recently developed on-shell methods for evaluating coefficients of loop integrals, introducing a discrete Fourier projection as a means of improving efficiency and numerical stability. We illustrate the numerical stability of our approach by computing and analyzing six-, seven- and eight-gluon amplitudes in QCD and comparing against previously-obtained analytic results.
Keywords
Cite
@article{arxiv.0803.4180,
title = {An Automated Implementation of On-Shell Methods for One-Loop Amplitudes},
author = {C. F. Berger and Z. Bern and L. J. Dixon and F. Febres Cordero and D. Forde and H. Ita and D. A. Kosower and D. Maitre},
journal= {arXiv preprint arXiv:0803.4180},
year = {2008}
}
Comments
38 pages, 10 figures, RevTex