Parton Distributions for Event Generators

TL;DR

This paper develops a new method to optimize parton distribution functions specifically for use with LHC event generators, enhancing the accuracy of predictions by integrating experimental data and theoretical cross sections.

Contribution

It introduces a generalized global QCD analysis that produces PDFs tailored for event generators, especially improving leading-order predictions at the LHC.

Findings

New PDF sets (CT09MCS, CT09MC1, CT09MC2) show improved agreement with LHC data.

Optimized PDFs enhance the reliability of event generator predictions.

Comparison with other approaches demonstrates the effectiveness of the new method.

Abstract

In this paper, conventional Global QCD analysis is generalized to produce parton distributions optimized for use with event generators at the LHC. This optimization is accomplished by combining the constraints due to existing hard-scattering experimental data with those from anticipated cross sections for key representative SM processes at LHC (by the best available theory) as joint input to the global analyses. The PDFs obtained in these new type of global analyses using matrix elements calculated in any given order will be best suited to work with event generators of that order, for predictions at the LHC. This is most useful for LO event generators at present. Results obtained from a few candidate PDF sets (labeled as CT09MCS, CT09MC1 and CT09MC2) for LO event generators produced in this way are compared with those from other approaches.