Speaker
Description
We present the MCscales approach for incorporating scale uncertainties in parton
distribution functions. The method builds on the Monte Carlo sampling method
for propagating experimental uncertainties to PDFs that underlies the NNPDF
approach, by extending it to the space of factorisation and renomalisation
scales for the processes entering a PDF fit. A prior probability is assigned to
each scale combinations affecting the PDF replicas 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 partonic cross section, thus
accounting for the full correlations between the two. We illustrate the
opportunities for phenomenological exploration made possible by our
methodology, by studying the correlations between scale variations in PDFs
and those in the partonic cross sections for a variety of LHC observables. Sets
of PDFs enriched with scale information are provided, along with a set of tools
to use them.
| Submitted on behalf of a Collaboration? | No |
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