aMCfast: automation of fast NLO computations for PDF fits

TL;DR

aMCfast automates the integration of NLO cross section calculations with PDF fitting tools, enabling quick and easy inclusion of new processes at the LHC without manual intervention.

Contribution

It introduces a fully automated interface between MadGraph5_aMC@NLO and APPLgrid, simplifying the process of incorporating NLO calculations into PDF fits.

Findings

Automated process integration reduces manual effort.

Enables inclusion of new LHC processes in PDF fits.

Demonstrates effectiveness with several measurable LHC processes.

Abstract

We present the interface between MadGraph5_aMC@NLO, a self-contained program that calculates cross sections up to next-to-leading order accuracy in an automated manner, and APPLgrid, a code that parametrises such cross sections in the form of look-up tables which can be used for the fast computations needed in the context of PDF fits. The main characteristic of this interface, which we dub aMCfast, is its being fully automated as well, which removes the need to extract manually the process-specific information for additional physics processes, as is the case with other matrix element calculators, and renders it straightforward to include any new process in the PDF fits. We demonstrate this by studying several cases which are easily measured at the LHC, have a good constraining power on PDFs, and some of which were previously unavailable in the form of a fast interface.