Techniques and calculations for SM phenomenology:
Calculations/tools:
expected precision for fundamental Standard Model processes at 14 and 100 TeV; what calculations are needed to match this precision?
NNLO and N3LO; status/challenges/prospects
theory uncertainties; more rigorous estimates? correlations? In particular, theory uncertainty for EW corrections?
usage of NNLO results; grids seem to be a real bottleneck now for precision work
resummation in analytic and parton shower calculations
uncertainty for 'softly-vetoed' distributions
comparisons of jet veto calculations
tuned comparison of NLL parton showers; sub-leading power corrections
PDFs:
followup on PDF4LHC21 benchmarking exercise; better understanding of tolerances, tensions
EW corrections/EW PDFs; how to provide consistent calculations (lepton definition with QED effects)
Electron-ion collider (EIC); what will EIC tell us? how do we prepare for that?
N3LO PDFS; how firm are changes to the gluon, and what should be done for benchmark Higgs cross sections; progress on splitting functions
PDF uncertainties, i.e. hopscotch vs Monte Carlo sampling
intrinsic charm
theory uncertainties/correlations in fit. Double counting?
quark-gluon discrimination for PDF determination
Higgs:
understanding the SM for high Higgs pT; role of top mass corrections/scheme (MSbar vs on-shell); how to improve channel sensitivities;
VBF signal at high pT; gluon-fusion background in VBF phase-space
parton-shower uncertainties in VBF
EW sector:
polarisation measurements (for diboson/VBS as well): theory/experiment interplay
prospects for tri-boson production. Are there any theoretical limitations for run III?
W mass:
(non-perturbative) modeling
new ideas/methods (asymmetry)
determination at e+e-
theory agnostic determination; how agnostic?
STXS for multiboson processes
Top:
ttW tension; multi-jet merging and other modelling aspects (including treatment in experiments)
merging of off-shell ttW with parton shower
modelling of ttbb
tt+X: on-shell vs. off-shell. role of single-top contributions
tt+gamma: modeling, in particular regarding on-shell/off-shell
Additional jet activity in top-quark pair production and decay
Jets:
flavor tagging of jets; matching what theorists can predict (IR safety) and what experimentalists can measure [overlap with Jet substructure techniques, see below]
use heavy flavor jets for W+c (→strange quark PDFs) and Z+c (→intrinsic charm)
further investigations/understanding of jet R-dependent scale uncertainties
Machine Learning
Matrix Element calculation using ML
Interpretable models
Fast surrogate models for physics simulations
Workflows and interoperability with experimental software
Incorporating uncertainties in the training of ML models
ML-based unfolding techniques
Enforcing properties to ML models: Lorentz invariance/equivariance, permutation invariance,
IRC safety
Jet substructure techniques:
detailed comparison between recently proposed jet flavour algorithms
starting from state-of-the-art ML-taggers, estimate how much they are correlated to the physics in the measurements of substructure we already have. Discuss good procedures to best tune MC to describe ML-taggers. Discuss good procedures to estimate uncertainties on ML-taggers, given the physics understanding of various effects (an example is scale-variations, where our constraints from data are certainly stronger than the factor 2 variations in many cases, but sometimes the opposite).
take stock of how well most recent generator developments have improved description of multiple new measurements of substructure. (Followup from a previous Les Houches 2015 on q/g-tagging)
Tools, Event Generators and Machine Learning:
Standard Model Higgs:
ggF
N3LO PDFs: Seems that aN3LO PDFs have a large impact, beyond the previously assigned PDF-TH uncert. Do other groups agree with this and how robust are these conclusions? Do cuts affect the conclusion and are the changes localised in PS? What other reasonable approximations could we make for comparison? (Related lit: 2207.04739)
ggF+jj as a background for VBF
EW Corrections: Various approximations seem to agree well with each other and the full result. Impact on STXS bins? (Related lit: 2010.09451)
B-quark issues
Backgrounds for Higgs processes (ttbb/ttH, V+HF/VH)
4FS/5FS (bbH, t/H/Z+j, ttbb, fused Monte Carlos) (e.g. 2006.10086, 2109.15039, 2207.11264)
Off-shell measurements
Challenges of multi-leg processes, e.g. ggVVjj very challenging matrix element, can/should we approximate it with matching/merging? Are new techniques helpful (e.g. OTTER)?
Interpreting off-shell measurements in terms of EFTs, how does this impact interpretation of width measurements? (Related lit: 2203.02418)
HH
EFTs (SMEFT/HEFT)
Constraining the Higgs self-coupling using H + HH, are other processes or HH channels beyond ggHH useful?
Currently using STXS for H input for self-coupling, it was not optimised for this, is there something better we can do here (e.g. fiducial differential measurements optimised for kappa_lam)?
STXS
v1.2 too aggressive binning (required merging bins upon analysis)
v1.3 binning less aggressive could be worth adding bins to highlight specific observables (e.g. CP-sensitive binning)
Integrating decays in STXS
Thinking about the HL-LHC and its sensitivity in combination with e+e- Higgs factory.
Backgrounds
Predictions+uncertainty models for backgrounds to ttH production: tt+HF, ggH+HF, tt+V, previous proposal was to estimate ttV EW correction in different phase space regions
Identifying backgrounds needed for other Higgs channels/measurements and what we can do to address them (see e.g. H background to HH, H+2j, ggVVjj, ttbb topics)