Dealing With Ambiguities in Higher Order {QCD} Predictions for Large Processes Involving Real Photons
May, 198644 pages
Published in:
- Nucl.Phys.B 286 (1987) 509-552
- Published: 1987
Report number:
- LPTHE ORSAY-86/14
Citations per year
Abstract: (Elsevier)
We discuss the ambiguities which affect predictions for large p T processes in the framework of perturbative QCD: indeed, the choice of both the renormalization scheme (RS) where the coupling constant is defined and of the factorization scheme (FS) connected with parametrization of long distance physics, is arbitrary. We specialize to the case of large p T processes involving real photons for which next to leading order calculations have been performed. The variation of the predictions for the inclusive spectrum with respect to RS and FS parameters is illustrated by predictions for the inclusive spectrum with respect to RS and FS parameters is illustrated by drawing contour lines. We discuss various algorithms to get rid of these ambiguities and give arguments to understand the shape of the contour plots and to show that all proposed algorithms yield, for reasonably large values of p T , very close answers. Also included is a discussion of the choice of scale for the Drell-Yan pair mass-distribution. We conclude by emphasizing that this treatment of ambiguities gives a sounder basis for comparing with experiment and extracting precise information about the values of λ and gluon properties.- QUANTUM CHROMODYNAMICS: PERTURBATION THEORY
- TRANSVERSE MOMENTUM: HIGH
- RENORMALIZATION: DEPENDENCE
- DEPENDENCE: FACTORIZATION
- MODEL: DRELL-YAN
- HADRON: PHOTOPRODUCTION
- PHOTOPRODUCTION: HADRON
- PHOTON: HADROPRODUCTION
- HADROPRODUCTION: PHOTON
- PHOTON: DIRECT PRODUCTION
References(0)
Figures(0)
Loading ...