NGluon: A package to calculate one-loop multi-gluon amplitudes

TY - JOUR

T1 - NGluon

T2 - A package to calculate one-loop multi-gluon amplitudes

AU - David Badger, Simon

AU - Biedermann, B.

AU - Uwer, P.

PY - 2011/8/1

Y1 - 2011/8/1

N2 - We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double precision the library yields reliable results for up to 14 gluons with only a small fraction of events requiring a re-evaluation using extended floating point arithmetic. We believe that the library presented here provides an important contribution to future LHC phenomenology. The program may also prove useful in cross checking results obtained by other methods. In addition, the code provides a sample implementation which may serve as a starting point for further developments. Program summary: Program title: NGluon Catalogue identifier: AEIZ-v1-0 Program summary URL: http://cpc.cs.qub.ac.uk/ summaries/AEIZ-v1-0.html Program obtainable from: CPC Program Library, Queen?s University, Belfast, N. Ireland Licensing provisions: GNU Public License No. of lines in distributed program, including test data, etc.: 30 677 No. of bytes in distributed program, including test data, etc.: 334 896 Distribution format: tar.gz Programming language: C++ Computer: Any computer platform supported by the GNU compiler suite. Operating system: No specific requirements - tested on Scientific Linux 5.2. RAM: Depending on the complexity, for realistic applications like 10 gluon production in double precision below 10 MB. Classification: 11.5 External routines: QCDLoop (http://qcdloop.fnal.gov/), qd (http://crd.lbl.gov/∼dhbailey/mpdist/) Nature of problem: Evaluation of next-to-leading order corrections for gluon scattering amplitudes in pure gauge theory. Solution method: Purely numerical approach based on tree amplitudes obtained via Berends-Giele recursion combined with unitarity method. Restrictions: Running in double precision the number of gluons should not exceed 14. Running time: Depending on the number of external gluons between less than a millisecond (4 gluons) up to a 1 s (14 gluons) per phase space point.

AB - We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double precision the library yields reliable results for up to 14 gluons with only a small fraction of events requiring a re-evaluation using extended floating point arithmetic. We believe that the library presented here provides an important contribution to future LHC phenomenology. The program may also prove useful in cross checking results obtained by other methods. In addition, the code provides a sample implementation which may serve as a starting point for further developments. Program summary: Program title: NGluon Catalogue identifier: AEIZ-v1-0 Program summary URL: http://cpc.cs.qub.ac.uk/ summaries/AEIZ-v1-0.html Program obtainable from: CPC Program Library, Queen?s University, Belfast, N. Ireland Licensing provisions: GNU Public License No. of lines in distributed program, including test data, etc.: 30 677 No. of bytes in distributed program, including test data, etc.: 334 896 Distribution format: tar.gz Programming language: C++ Computer: Any computer platform supported by the GNU compiler suite. Operating system: No specific requirements - tested on Scientific Linux 5.2. RAM: Depending on the complexity, for realistic applications like 10 gluon production in double precision below 10 MB. Classification: 11.5 External routines: QCDLoop (http://qcdloop.fnal.gov/), qd (http://crd.lbl.gov/∼dhbailey/mpdist/) Nature of problem: Evaluation of next-to-leading order corrections for gluon scattering amplitudes in pure gauge theory. Solution method: Purely numerical approach based on tree amplitudes obtained via Berends-Giele recursion combined with unitarity method. Restrictions: Running in double precision the number of gluons should not exceed 14. Running time: Depending on the number of external gluons between less than a millisecond (4 gluons) up to a 1 s (14 gluons) per phase space point.

U2 - 10.1016/j.cpc.2011.04.008

DO - 10.1016/j.cpc.2011.04.008

M3 - Journal article

SN - 0010-4655

VL - 182

SP - 1674

EP - 1692

JO - Computer Physics Communications

JF - Computer Physics Communications

IS - 8

ER -