Efficient evolution of unpolarized and polarized parton distributions with QCD-PEGASUS
Aug, 200435 pages
Published in:
- Comput.Phys.Commun. 170 (2005) 65-92
e-Print:
- hep-ph/0408244 [hep-ph]
Report number:
- NIKHEF-04-011
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Abstract: (arXiv)
The Fortran package QCD-PEGASUS is presented. This program provides fast, flexible and accurate solutions of the evolution equations for unpolarized and polarized parton distributions of hadrons in perturbative QCD. The evolution is performed using the symbolic moment-space solutions on a one-fits-all Mellin inversion contour. User options include the order of the evolution including the next-to-next-to-leading order in the unpolarized case, the type of the evolution including an emulation of brute-force solutions, the evolution with a fixed number n_f of flavours or in the variable-n_f scheme, and the evolution with a renormalization scale unequal to the factorization scale. The initial distributions are needed in a form facilitating the computation of the complex Mellin moments.Note:
- 36 pages, LaTeX, 2 eps-figures. The program code is included in tarred/gzipped form (file 'pegasus.tar.gz') and can be obtained by downloading the source of this article
- Unpolarized and longitudinally polarized parton distributions
- Altarelli-Parisi evolution equations
- Mellin-space solutions
- nucleon: structure function
- parton: momentum spectrum
- polarization: longitudinal
- quantum chromodynamics
- perturbation theory: higher-order
- quark: flavor
- Mellin transformation
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