HELAC-Onia: an automatic matrix element generator for heavy quarkonium physics
Abstract
By the virtues of the Dyson-Schwinger equations, we upgrade the published code \mtt{HELAC} to be capable to calculate the heavy quarkonium helicity amplitudes in the framework of NRQCD factorization, which we dub \mtt{HELAC-Onia}. We rewrote the original \mtt{HELAC} to make the new program be able to calculate helicity amplitudes of multi P-wave quarkonium states production at hadron colliders and electron-positron colliders by including new P-wave off-shell currents. Therefore, besides the high efficiencies in computation of multi-leg processes within the Standard Model, \mtt{HELAC-Onia} is also sufficiently numerical stable in dealing with P-wave quarkonia (e.g. ) and P-wave color-octet intermediate states. To the best of our knowledge, it is a first general-purpose automatic quarkonium matrix elements generator based on recursion relations on the market.
Keywords
Cite
@article{arxiv.1212.5293,
title = {HELAC-Onia: an automatic matrix element generator for heavy quarkonium physics},
author = {Hua-Sheng Shao},
journal= {arXiv preprint arXiv:1212.5293},
year = {2013}
}
Comments
Published version. 24 pages,1 figure, 7 tables, HELAC-Onia is available from http://helac-phegas.web.cern.ch/helac-phegas