Les Houches

Slack channel: #np-ps-syst-uncs

Possible projects:

• Shower accuracy and benchmarks
• Amplitude evolution, if people are interested
• Role and impact of the infrared cutoff, tuning, and uncertainties
• A practical approach for experiments
  • What comparisons make sense - what is available?
  • Generators wishlist?
• Including systematic uncertainties in ML based analysis

Interested people: Josh, Simon, Stefan, Vinny, Axel, Aishik, Saptaparna, Andrzej, Ana, Maria V., Gianna, Chris G, Christian P, Max, Peter M

Agreed projects:

1. Perturbative benchmarks of showers [Simon, James, Daniel]
   1. NLL, Numerical impacts
2. Interplay between shower and hadronisation [Simon]
   1. Extending study from LH17 arXiv:1803.07977
   2. Effective/comprehensive uncertainty band
3. Uncertainty recommendation using available tools [Josh]
   1. Setup 4-point variations of all combinations of shower and hadronisation model
   2. Tune these in a consistent way to get an uncertainty envelope
4. Tuning strategies [Stefan K]
   1. What is currently done?
   2. Common framework?
   3. Better documentation of existing framework
   4. Benchmark sets of data

Slack channel: #gen-soft-comp

Possible projects:

• Efficiencies
• MC reweighting/unweighting
• GPU/Vectorisation
• Event format/sharing
• Containerisation/preservation/reproducibility
• Use of ML
• Common frameworks

Interested people: Josh, Vinny, Andrea, Stefan, Saptaparna, Maria V., Sergio, Chris G, Christian P, Ana, Max, Peter M, Simon

Agreed projects:

1. GPU/Vectorisation/HPC [Josh]
   1. Experience porting codes
   2. Workflows in experiments
      1. How would code be run in practise
      2. How to get/confirm allocations
      3. Sharing of resources between EXP and TH
2. Computing performance [Josh]
   1. Benchmarking current code
      1. Also with examples from EXP
   2. Accounting in experiments
   3. Projections for future N(2,3)LO calculations
3. Updates to interfaces [Josh]
   1. Interoperability of models
   2. Modular framework
   3. Multi-event API in MC generators
      1. Resampling
4. Accessibility of tools [Josh]
   1. Containerisation and reproducibility
      1. Docker images, run cards, Rivet routines, Yoda files → HepData
      2. Use these tools to make LH studies reproducible
      3. Can at Docker-based workflow on e.g. lxplus be documented to lower barrier to entry for MC studies?
      4. Make sure cards actually used by EXP are uploaded with TH prediction Yoda files.
      5. Make available for benchmarking (c.f. point 2.), including full chain in EXP
   2. MC Generation generic tool/interface
      1. Like MCPlots
5. Event formats [Josh]
   1. New HDF5 standard ← LHEF/HepMC
      1. Easier event sharing, smaller disk footprint
   2. Need for more information in intermediate stages of generation?
   3. Sample sharing between experiments
      1. Joint/cross validation
6. ML for MC []
   1. Interoperability link to point 3. (swapping out parts of generation in modular framework)
   2. Discussion of exact vs approximate use of ML
7. Resampling/reweighting [Josh]
   1. Reweighting and derivative-based optimisation
   2. Resampling to eliminate negative weights
      1. NN and cell-based tools
      2. Stress tests of these tools?
         1. Problem areas from TH PoV
         2. Validation at scale in EXP

Slack channel: #ttw

Possible projects:

• Understanding differences between Sherpa MEPS@NLO and aMC+Py8 FxFx?
• Modelling uncertainties?

Interested people: Josh, Sergio, Stefan, Gianna

Slack channel: #ew-evo-id

• Possibly connecting to ttW?

Interested people: Simon, Axel, Andrzej

• Hadronization model should respond to shower IR cut variations
• Study IR ctuoff dependence, map out how purely perturbative variations compare
• goal is to update the LH 17 study on retuning with a more solid theory framework

Interested: Simon, Andrzej, Stefan K.

• Linked to Jets and Higgs

Interested people: Simon, Andrzej

• Linked to Higgs

Interested people: Simon, Josh, Stefan, Axel, Saptaparna

• Linked with Higgs and Jets

Interested people: Josh, Davide?, Stefan

Possible projects:

• New unfolding observables
• Interoperability/practical considerations

Interested people: Vinny,Josh, Aishik, Andrzej, Maria V., Peter M

Slack channel: #lhc-fpf

(Possibly the same for DUNE and EIC if enough people are here?)

Possible projects:

• Impact of NNPDF + FPF data on LHC precision, e.g. W-mass

Interested people: Josh, Maria V., Stefan, Peter M (EIC)