On the maximal use of Monte Carlo samples: re-weighting events at NLO accuracy

TL;DR

This paper introduces a method to efficiently re-use Monte Carlo event samples at NLO accuracy for high-energy physics simulations, reducing computational costs while maintaining precision.

Contribution

The authors develop and implement a re-weighting technique in MadGraph5_aMC@NLO that allows re-using parton-level samples under different theoretical assumptions.

Findings

Method validated on multiple LHC physics cases

Significant reduction in simulation costs

Maintains NLO accuracy in re-weighted samples

Abstract

Accurate Monte Carlo simulations for high-energy events at CERN's Large Hadron Collider, are very expensive, both from the computing and storage points of view. We describe a method that allows to consistently re-use parton-level samples accurate up to NLO in QCD under different theoretical hypotheses. We implement it in MadGraph5_aMC@NLO and show its validation by applying it to several cases of practical interest for the search of new physics at the LHC.