Abstract
We explore connections between two common methods for quantifying the
uncertainty in parton distribution functions (PDFs), based on the Hessian error
matrix and Monte-Carlo sampling. CT14 parton distributions in the Hessian
representation are converted into Monte-Carlo replicas by a numerical method
that reproduces important properties of CT14 Hessian PDFs: the asymmetry of
CT14 uncertainties and positivity of individual parton distributions. The
ensembles of CT14 Monte-Carlo replicas constructed this way at NNLO and NLO are
suitable for various collider applications, such as cross section reweighting.
Master formulas for computation of asymmetric standard deviations in the
Monte-Carlo representation are derived. A numerical program is made available
for conversion of Hessian PDFs into Monte-Carlo replicas according to normal,
log-normal, and Watt-Thorne sampling procedures.
Users
Please
log in to take part in the discussion (add own reviews or comments).