| 1. |
- Aad, G., et al.
(författare)
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Emulating the impact of additional proton–proton interactions in the ATLAS simulation by presampling sets of inelastic Monte Carlo events
- 2022
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Ingår i: Computing and Software for Big Science. - : Springer Science and Business Media LLC. - 2510-2044 .- 2510-2036. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
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| 2. |
- Albrecht, J, et al.
(författare)
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A Roadmap for HEP Software and Computing R&D for the 2020s
- 2019
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Ingår i: Computing and Software for Big Science. - : Springer Science and Business Media LLC. - 2510-2044 .- 2510-2036. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.
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| 3. |
- Mullier, G.A., et al.
(författare)
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AtlFast3 : The Next Generation of Fast Simulation in ATLAS
- 2022
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Ingår i: Computing and Software for Big Science. - : Springer Science and Business Media LLC. - 2510-2044 .- 2510-2036. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS experiment at the Large Hadron Collider has a broad physics programme ranging from precision measurements to direct searches for new particles and new interactions, requiring ever larger and ever more accurate datasets of simulated Monte Carlo events. Detector simulation with GEANT4 is accurate but requires significant CPU resources. Over the past decade, ATLAS has developed and utilized tools that replace the most CPU-intensive component of the simulation—the calorimeter shower simulation—with faster simulation methods. Here, AtlFast3, the next generation of high-accuracy fast simulation in ATLAS, is introduced. AtlFast3 combines parameterized approaches with machine-learning techniques and is deployed to meet current and future computing challenges, and simulation needs of the ATLAS experiment. With highly accurate performance and significantly improved modelling of substructure within jets, AtlFast3 can simulate large numbers of events for a wide range of physics processes.
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| 4. |
- Valassi, Andrea, et al.
(författare)
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Challenges in Monte Carlo Event Generator Software for High-Luminosity LHC
- 2021
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Ingår i: Computing and Software for Big Science. - : Springer Science and Business Media LLC. - 2510-2044 .- 2510-2036. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- We review the main software and computing challenges for the Monte Carlo physics event generators used by the LHC experiments, in view of the High-Luminosity LHC (HL-LHC) physics programme. This paper has been prepared by the HEP Software Foundation (HSF) Physics Event Generator Working Group as an input to the LHCC review of HL-LHC computing, which has started in May 2020.
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| 5. |
- Aad, G., et al.
(författare)
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Software Performance of the ATLAS Track Reconstruction for LHC Run 3
- 2024
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Ingår i: Computing and Software for Big Science. - : Springer Nature. - 2510-2044. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Charged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pile-up) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two. © The Author(s) 2024.
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