Parton distributions with scale uncertainties: a Monte Carlo sampling approach

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