Treatment of theory uncertainties
- Some theory uncertainties on the input processes are already baked into the covariance matrices (all uncertainties for Higgs, uncertainties on acceptance only for SM fiducial cross-sections)
- EFT parameterization uncertainties are not considered for the moment
- Computing scale variations on EFT predictions should be possible in the MG setups used to derive the parameterizations.
- Technically EFT uncertainties are easy to add (the machinery for adding them through nuisance parameters is already available), but this would require a recipe on how to treat uncertainty correlations (between coefficients, measurement regions, etc.).
- Similar formats from CMS and ATLAS, will try to converge on a common version
- Preference for using dictionaries whenever possible as this is self-documenting and easier to extend if we want to add more information.
- Need to define a set of tools to use to run the full chain, ideally with proper version numbers, etc.
- In CMS the EFT2Obs package contains all the necessary tools
- ATLAS looking at solutions based on a docker image containing the necessary tools. Not in common use by the theory community, but could at least extract the tool information from the docker config.
- Preference for moving away from ROOT whenever possible
- Preference for not relying on CVMFS (the shared filesystem used by ATLAS/CMS to access common tool repositories for LCG grid computing) as this is not widely usable by theorists
Configurations for EFT generation
- Need to ensure the full generation config is specified through MG cards
- Will try to harmonize ATLAS and CMS options as much as possible
- Will get in touch with Area 2 which is probably the better home for this effort.
- Tests on pT or angular variables (even less correlated with the q^2) should provide interesting information
- Could also consider interpretations in a particular UV model, comparing the straight-to-UV case (measurement -> UV) with the two step interpretation through SMEFT (measurement -> SMEFT -> UV). For the latter, some truncations could be investigated and compared with the straight-to-UV case.
- Document all the links to the code / inputs on the Area 4 twiki page
- Converge on a yaml format for parameterisations and measurements
- Sets of yaml files from each experiment will then be exchanged
- Perform a quick cross-check of the fit to each parameter from the CMS+ATLAS combination
- In parallel CMS will improve the Higgs parameterisations (e.g. to include all STXS bins and the decay side)
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