Spinney: A Form library for helicity spinors

Abstract

In this work, the library spinney is presented, which provides an implementation of helicity spinors and related algorithms for the symbolical manipulation program Form. The package is well suited for symbolic amplitude calculations both in traditional, Feynman diagram based approaches and unitarity-based techniques. Program summary Program title: spinney Catalogue identifier: AEJQ_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEJQ_v1_0.html Program obtainable from: CPC Program Library, Queenʼs University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 21 128 No. of bytes in distributed program, including test data, etc.: 377 589 Distribution format: tar.gz Programming language: Form Computer: Any supporting the Form language Operating system: Any supporting the Form language Classification: 4.4, 5, 11.1 Nature of problem: Implementation of the spinor-helicity formalism Solution method: Form implementation Running time: From actual calculations of all six-point one-loop diagrams of the process g g → q q ¯ q ′ q ¯ ′ bounds of 50 ms < t ⩽ 71 s for the simplest and the most complicated diagram respectively have been derived on an Intel Xeon 3.20 GHz using Form 3.3.