23–28 Oct 2022
Villa Romanazzi Carducci, Bari, Italy
Europe/Rome timezone

Accelerating LHC event generation with simplified pilot runs and fast PDFs

24 Oct 2022, 15:30
20m
Sala A+A1 (Villa Romanazzi)

Sala A+A1

Villa Romanazzi

Oral Track 3: Computations in Theoretical Physics: Techniques and Methods Track 3: Computations in Theoretical Physics: Techniques and Methods

Speaker

Christian Gutschow (UCL (UK))

Description

High-precision calculations are an indispensable ingredient to the success of the LHC physics programme, yet their poor computing efficiency has been a growing cause for concern, threatening to become a paralysing bottleneck in the coming years. We present solutions to eliminate the apprehension by focussing on two major components of general purpose Monte Carlo event generators: The evaluation of parton-distribution functions along with the generation of perturbative matrix elements. We show that for the cost-driving event samples employed by the ATLAS experiment to model omnipresent irreducible Standard Model backgrounds, such as weak boson+jets as well as top-quark-pair production, these components dominate the overall run time by up to 80%. We demonstrate that a reduction of the computing footprint of LHAPDF and SHERPA by factors of around 50 can be achieved for multi-leg NLO event generation, thereby smashing one of the major milestones set by the HSF event generator working group whilst paving the way towards affordable state-of-the-art event simulation in the HL-LHC era.

References

in preparation

Significance

This presentation covers a new targeted effort enabled by the SWIFT-HEP project, bringing together experimentalists and MC developers to greatly improve the computational efficiency of multi-leg NLO calculations, following a dedicated CPU profiling of these setups - typically the most expensive ones produced by the LHC experiments. The resulting improvements achieve a significant milestone set by the HSF generators working group and will help the experiments stay within the projected budget in the coming years by making high-precision calculations more affordable as we head into the high-luminosity phase of the LHC.

Experiment context, if any relevant for the LHC experiments, mainly ATLAS and CMS (abstract does not require involvement of the experiments' publication boards)

Primary authors

Andy Buckley (University of Glasgow (GB)) Christian Gutschow (UCL (UK)) Enrico Bothmann (University of Göttingen) Marek Schoenherr (University of Durham) Max Knobbe Stefan Hoeche (Fermilab)

Presentation materials

Peer reviewing

Paper