Tests of performance of the fit in a global QCD analysis

25 Mar 2020, 11:00
20m
Brooklyn, NY

Brooklyn, NY

333 Adams Street, Brooklyn, New York 11201, USA
Contributed Talk Electroweak Physics and Beyond the Standard Model Electroweak Physics and Beyond the Standard Model

Speaker

Pavel Nadolsky (Southern Methodist University)

Description

The span of uncertainties of the PDFs obtained in a global analysis depends on criteria for selection of acceptable PDF fits. I review several such criteria for estimating the goodness of fit in a large-scale analysis such as CT18, where they are applied in addition to the commonly used value of the global log-likelihood. On the example of CT18(Z) predictions for electroweak precision observables, I show that these tests offer in-depth insights about agreement among constraints from individual experiments and other such factors that ultimately determine the realistic PDF uncertainty. I compare two particularly helpful statistical techniques for this purpose, Lagrange Multiplier scans and Hessian sensitivities.

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