Parton distributions with scale uncertainties: a MonteCarlo sampling approach

Abstract

We present the MCscales approach for incorporating scale uncertainties in parton distribution functions (PDFs). The new methodology builds on the Monte Carlo sampling for propagating experimental uncertainties into the PDF space that underlies the NNPDF approach, but it extends it to the space of factorisation and renomalisation scales. A prior probability is assigned to each scale combinations set in the theoretical predictions used to obtain each PDF replica in the Monte Carlo ensemble and a posterior probability is obtained by selecting replicas that satisfy fit-quality criteria. Our approach allows one to exactly match the scale variations in the PDFs with those in the computation of the partonic cross sections, thus accounting for the full correlations between the two. We illustrate the opportunities for phenomenological exploration made possible by our methodology for a variety of LHC observables. Sets of PDFs enriched with scale information are provided, along with a set of tools to use them.

arXiv comment41 pages, 12 figures

References in corpus (38)

• Parton distributions for the LHC Run II
• Parton distributions with LHC data
• LHAPDF6: parton density access in the LHC precision era
• Parton distributions from high-precision collider data
• Top++: a program for the calculation of the top-pair cross-section at hadron colliders
• New CTEQ global analysis of quantum chromodynamics with high-precision data from the LHC
• Higgs boson gluon-fusion production in N3LO QCD
• FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order
• Parton distributions from LHC, HERA, Tevatron and fixed target data: MSHT20 PDFs
• The Path to Proton Structure at One-Percent Accuracy
• A first unbiased global NLO determination of parton distributions and their uncertainties
• Combining QCD and electroweak corrections to dilepton production in FEWZ
• A posteriori inclusion of parton density functions in NLO QCD final-state calculations at hadron colliders: The APPLGRID Project
• Higgs Boson Production at Hadron Colliders at N3LO in QCD
• The PDF4LHC21 combination of global PDF fits for the LHC Run III
• Vector-boson fusion Higgs production at N${}^3$LO in QCD
• Parton Distribution Benchmarking with LHC Data
• Fitting Parton Distribution Data with Multiplicative Normalization Uncertainties
• Meaningful characterisation of perturbative theoretical uncertainties
• Snowmass 2021 whitepaper: Proton structure at the precision frontier
• Approximate N${}^3$LO Parton Distribution Functions with Theoretical Uncertainties: MSHT20aN${}^3$LO PDFs
• fastNLO: Fast pQCD Calculations for PDF Fits
• On the Higgs cross section at N${}^3$LO+N${}^3$LL and its uncertainty
• APFELgrid: a high performance tool for parton density determinations
• Towards Ultimate Parton Distributions at the High-Luminosity LHC
• Parton distributions in the SMEFT from high-energy Drell-Yan tails
• Bayesian Approach to Inverse Problems: an Application to NNPDF Closure Testing
• PineAPPL: combining EW and QCD corrections for fast evaluation of LHC processes
• Updated Higgs cross section at approximate N${}^3$LO
• Probabilistic definition of the perturbative theoretical uncertainty from missing higher orders
• How well can we guess theoretical uncertainties?
• On the Consistent Use of Scale Variations in PDF Fits and Predictions
• Why ${\alpha }_s$ Cannot be Determined from Hadronic Processes without Simultaneously Determining the Parton Distributions
• Deuteron Uncertainties in the Determination of Proton PDFs
• Correlation of Theoretical Uncertainties in PDF Fits and Theoretical Uncertainties in Predictions
• Future tests of parton distributions
• The dark side of the proton
• An analysis of Bayesian estimates for missing higher orders in perturbative calculations

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