Session 1: brief review of combined EFT fits and constraints
9 TopFitter (White)
- Warsaw basis: 16 operators affecting top; data constrain 12 operators, neglect others
- correlations included where available
- should we set all but one to zero to understand individual measurements?
-> has to be presented carefully, not an actual EFT parameter fit
- which operators are primarily constrained by quadratic terms? cG, maybe 4-fermion?
-> paper says linear operators included?
- scale of validity quoted? No but removing Mtt overflow bin did not make much difference
- could you determine the goodness of fit for the SM only?
- What about alternate approach from Butterworth: assume data is SM and constrain c's assuming
they are zero? Is that a circular approach?
- any issue with fitting particle-level vs parton-level? No.
-> should experimentalists be the ones evaluating particle->parton uncertainties?
- should we make measurements of distributions before background subtraction? Yes.
9:30 Higgs + dibosons + jets (Plehn)
- Include Dphi(jj) but do not fit CP-odd operators for philosophical reasons
- no experimental combination of dibosons (only ATLAS+CMS ZZ)
- quark 4-fermion operators constrained by 2-3 jets, interference term is zero
- three-gluon operator constrained by >=5 jets
- constraints are at a high scale, can we apply them to Higgs physics? Consensus is yes.
- What about (DG)^2? Not in Warsaw, becomes a 4-fermion operator (constrained by 2-3 jets).
- m4l gives little information within the context of VBF -- adding ggF should increase its contribution
10 EW precision & low energy (Trott)
- EDM strongly constrains CP-odd operators in Higgs & top physics
-> motivates fits either requiring MFV or CP-even
- Benefit to using mW,mZ,GF input scheme because there are two scales (alphaEM would be third)
- EFT uncertainties can be important for precision EW data (higher order terms ~10% of leading terms)
Session 2: status of constraints within LHC experiments
11 Higgs STXS vs data (Hays/Zemaityte)
- note that including quadratic terms becomes more valid when measurements are precise
- should only truncate based on IR physics or MFV symmetry assumption
-> will truncate using only assumed symmetries
- should remove coefficients from operators and include top loop in ggF
- should include ~1% uncertainty on S parameter from higher order effects
11:30 Higgs DiffXS (Pilkington)
- which is more sensitive: two 1d distributions with correlation or 2d distribution? Could check.
-> significant gain expected from 2d distribution in VBF
12 Electroweak (Lohwasser/Price)
- Publish observed numbers of data events? Useful if validated Delphes model provided.
- Should quote limits from fully optimized reconstructed data and compare to those from unfolded data
12:30 CMS (Milenovic)
- will CMS provide correlations in diffXS? Aiming to do so, probably starting from 2017 data
- will CMS present results using YR4 PO notation? Yes, along with historical presentation.
Session 3: future tools/studies in dim-6 (LO & NLO) and dim-8 EFT
14 Warsaw LO UFO (Brivio)
- two implementations of Warsaw basis will soon be available
- ~30 operators if considering W/Z/H pole observables
- first fit probably also needs qq->ttbar?
14:30 Warsaw NLO QCD (Maltoni)
- many NLO SMEFT calculations available
- need to implement four-fermion terms before releasing NLO Madgraph implementation
-> Provide ggF as a starting point to study?
15 Dim 8 (Sanz)
- no new q^2 dependence coming from dim-8 -- could be due to basis?
- Need to check vertices with fermions: q^2 dependence might come from spinors
- useful for systematic checks
- can VBF be added? more complicated but possible in principle
Session 4: fit issues
16 Uncertainties (Pecjak)
- Can Madgraph include the running of the EFT operators so that we can use it for EFT scale variations?
16:30: Validity (Hays/Spannowsky)
- For a given validity scale what range of c should we allow? Up to ~10 okay.
- What should we do about coefficients that are directly probed above the scale used in the fit? Set to zero?