Uncertainties of predictions from parton distribution functions. 2. The Hessian method
Jan, 2001
30 pages
Published in:
- Phys.Rev.D 65 (2001) 014013
e-Print:
- hep-ph/0101032 [hep-ph]
Report number:
- MSU-HEP-07101,
- CERN-TH-2000-360
View in:
Citations per year
Abstract:
We develop a general method to quantify the uncertainties of parton distribution functions and their physical predictions, with emphasis on incorporating all relevant experimental constraints. The method uses the Hessian formalism to study an effective chi-squared function that quantifies the fit between theory and experiment. Key ingredients are a recently developed iterative procedure to calculate the Hessian matrix in the difficult global analysis environment, and the use of parameters defined as components along appropriately normalized eigenvectors. The result is a set of 2d Eigenvector Basis parton distributions (where d=16 is the number of parton parameters) from which the uncertainty on any physical quantity due to the uncertainty in parton distributions can be calculated. We illustrate the method by applying it to calculate uncertainties of gluon and quark distribution functions, W boson rapidity distributions, and the correlation between W and Z production cross sections.- 12.38.-t
- quantum chromodynamics
- momentum spectrum: parton
- statistical analysis
- data analysis method
- p p: inclusive reaction
- anti-p p: inclusive reaction
- W+: hadroproduction
- rapidity spectrum
- Z0: hadroproduction
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