====== Topics for Consideration ====== //(Editing this page requires special privileges: Conveners, managers)// **__List of brainstorming session June 6__** === Jets === * machine learning * comprehensive 2-prong study (non-b tags) (W-boson polarization) * alpha_s extraction from jet substructure (white whale) e.g. running at high scales (?) * assess complementarity to 3-jet/2-jet ratio (or other canonical observables) * use cases of quark/gluon tagging (e.g. in H+jets); use in NNLO? * jet substructure for understanding showers * J/Psi in jets, hybrid substructure, flavour tagging * fat jet definition === parton shower issues === * matching variations *study angularities *beyond LL uncertainties *shower starting scale choice (e.g. consistency conditions, test limits) * comprehensive shower tuning (+had+MPI) + PDF order * heavy flavour modelling * resummation versus fixed order e.g. tT + jets (in jet bins) * study tTbB, scale/shower uncertainties, large differences between generators? * non-global observables, colour correlations === resonance aware matching (tT) === [[ 2017:groups:tools:resonance_aware | wiki]] === scale choices === * LH Accord for scale variations? [discussion on: **Thu June 8th, 09h00-10h30**] * test case e.g. jet-veto cross section in Drell-Yan (+ N jets) === PDFs === * tensions within exp. data sets * theory uncertainties === EW corrections [discussion on: Fri June 9th, 16h30-18h00] === * automation * renormalization * treatment of resonances * democratic clustering * additive/multiplicative * scale choice === NNLO === * comparison of IR subtraction schemes [discussion on: **Wed June 7th, 10h30-12h30**] * Ntuples, grids, non-author use (also for NLO use) [discussion on: **Thu June 8th, 14h00-15h30**] * standards for public multi-loop results (e.g. Loopedia) [discussion on: **Fri June 9th, 14h00-16h00**] * NNLO+PS === Higgs === * simplified template cross sections (STXS Higgs)(also fiducial/differential cross sections) ( [[ 2017:groups:higgs:stxs | wiki ]] ) * boosted H -> bB * H differential * t/b mass effects * (N)NLO di-Higgs, gg -> ZH * H total XS * off-shell Higgs * questions in VBF === SM backgrounds for DM searches (V+jets) === * ratio Z/gamma, Z/W [discussion on: **Fri June 9th, 09h00-10h30**] * VH (H->bb), correlated scale variations * tT+gamma/Z === 4-dim methods === === wishlist update === === Vector boson scattering === * LO vs NLO, MC uncertainties, connection to VBF **__List of brainstorming session June 15__** === Recasting === * Long-Lived Particles * How to use Correlation information * Fastsim vs smearing? * Simplified Likelyhood framework * Long-Lived Particles * Making analysis easier to recast? * Analysis description accord === Long-Lived Particles === * Simplified Models * Zoology * Displaced vertices and baryogensis * Displaced tracks === Higgs === * Multiplet structure, LHC e+e-, gravitational waves * ggH at high pT * Couplings * Interference * Long Lived particles from Higgs * Light (< 100 GeV) Scalars (Higgs) * new variables * Data interpretation * BSM Higgs new signals, exotic decays * EFT * Di-Higgs * BSM Impact * EW phase-transition, baryogenesis * Couplings to light fermions === Dark Matter === * New Models/Portals and LHC signatures * heavy flavour signatures * New searches * "Dark" parton showers === SUSY === * Low MET * RPV * High multiplicity === Lepton non-universality === * Leptoquarks * other? * SM explanations * Links to DM and g-2 NP@LHCb === Other === * Vector-like quarks missing signatures * Missing resonance signals * Radion production @LHC * New models in MC? * Clockwork * Naturalness * Neutral Naturalness * EFT * NLO Tools * Strong Dynamics * Composite Higgs * BSM in top quark physics * LHC and flavour in New Physics * CP violation * Light particles * Beyond 14 TeV * New pheno **__Preliminary lists (before start of the workshop)__** ==== MC and Tools ==== - (from ER,SP,VC) - * pt_Z at medium-large pt: few percent precision might require assessing impact of NP corrections; MC study ? * subleading-log effects in parton showering: find the best variables to test them, and motivate an experimental analysis? * NNLO+PS: how well do these tools work in regions where logs are large? * Matching/merging uncertainties in jet substructure analysis: impact on jet-substructure tool performance * Resonance-aware matching schemes: a comparison could be instructive at this point, possibly in the context of m_top measurements. [can use this study to finally promote the use of the (already existing) LHE-to-PS modern interface capable for example to handle multiple veto-scales] * A guideline for assessing uncertainties in NLO+PS matching: is this realistic? Can we find a balance between being fully conservative and its opposite? * EW showers vs. EW corrections at fixed-order: a dedicated comparison? * g -> bbar , g-> ccbar -(from JH) *followup on Higgs+jets study from LH2015 *new study with inclusive jets *do parton showers have an impact on inclusive jet cross sections? *if all PS do not have a similar behavior, then why *do we understand in detail variations between various parton showers starting with as similar parameters as possible *can we benchmark "true" uncertainties *comparison of jet shapes at NLO/NNLO, PS and ME+PS *what is the role of UE when jet area subtraction is universally used ==== SM NLO/NNLO ==== == NNLO (from GH) == * status wishlist * to which extent is automation possible? * availabitity to non-authors * scale choices * power corrections * methods for IR subtractions, e.g. pro's and con's of N-Jettiness * NNLO+PS (see above) == NNLO (additions from JH) == *scale choices at NLO and NNLO *how "universal" (/"good") is HT/2 *scale choices for complex final states *comparison of power corrections for H+jet to W/Z+jet == NLO EW corrections (from SK) == * status wishlist * combination with (N)NLO QCD results (additive, multiplicative) * inclusion of corrections beyond NLO (multiphoton emission, NLL Sudakov approximation of leading NNLO EW effects) * uncertainty estimates * treatment of resolved real-radiation photons (fully inclusive, vetoes) * public availability == mixed QCD-EW corrections == == PDFs== * how to make use of NNLO results == PDFs (additions from JH) == * inclusion of scale uncertainties * scale choice for inclusive jets (pTjet vs pTjetmax) * impact of new processes at NNLO (tT, photon+jet, dijet,W/Z+jet) * dealing with disagreements between observables/experiments == photons == *isolation for photons at NNLO == future colliders == == ME+PS (from KT) == * NLO+PS can (yet) fully replace the usage of LO+PS in physics analyses ? [practical issues to be discussed] * Dealing with the large fraction of negative weights * LO+PS reweighed to NLO+PS, how to (not) do this for specific candles (Z/γ, W) * scale variations/choices and their interpretation as uncertainties * VBF (V)V+2j with (N)LO+PS, QCD-EW interference and ME+PS matching, VBF signal definition * photon+jets and matching with QED/QCD showers, QCD/EW corrections == Modelling of W and Z/γ at high, medium and low PT (from KT) == * LO+PS, NLO+PS, EW corrections on NLO+PS, NNLO+NNLL+PS, NLO QCD+EW + PS * low/medium PT what combination(s) to use for precision measurements and uncertainty envelopes * high PT and QCD+EW corrections * QCD/QED shower corrections + uncertainties at low/medium/high * resummation == Jet Physics (core dump from Jesse) == * Closing the loop on quark/quark tagging * From the LH 2015 parton shower comparison study… * …to a concrete plan of action for LHC jet shape measurements * Improved PDF constraints from quark/gluon tagging * “Deep learning” meets “deep thinking” * Interface of machine learning and analytic calculations * Multi-category classification * Physics-inspired network design * Jet substructure for tagging * Interplay of jet radius, jet grooming, and jet discriminants * Tagging longitudinal versus transverse W/Z bosons * Impact of soft QCD (underlying event) and pileup * Groomed jets for precision physics * Top mass determination * alpha_s extraction from substructure * Jets and heavy flavor * Color flow/dead cone in top quarks * Jet substructure of b/c-tagged jets, gluon splitting to heavy flavor * Charmonium polarization in identified jets * Heavy ion physics * Jet shapes in medium * Probe quark/gluon plasma with boosted objects ==== BSM ==== * "The Lifetime Frontier at the LHC": Common language/signature space for displaced vertices. * "Beyond Missing Energy": Do we have full coverage (if such a thing can be well-defined ) of BSM signatures which do not involve MET? E.g. R-parity violating SUSY, ... * "Multiple unknowns": most searches hunt for one new particle (+ MET in SUSY). How difficult is it to expand to multiple unknown particles? Does this add a lot of phase space coverage? * ' Beyond ATLAS and CMS': BSM at LHCb (and even ALICE). What more can be done with LHCb? Can we find BSM in forward/diffractive physics at all? * Colliders and multi-component dark matter * ... * Of course, new ideas or new features from old ideas are always welcome! ==== BMS tools and MC (from LP, FM,PR) ==== * EFT top/Higgs : basis, NLO corrections, applications… * Dark Matter specific tools: current challenges for s-channel/t-channel simplified models. NLO? * Recasting/presenting experimental results * Simplified Models * MC comparisons in BMS phase spaces (in overlap with SM session) * Boosted SM objects as probes for BSM searches (in overlap with SM session) ==== Higgs Physics ==== * Heavy flavor modeling (in the context of ttH, overlap with MC and tools) * Quark-mass effects in inclusive and exclusive distributions (H+(N)j, ZH, HH) * Simplified template cross sections * Status of measurements and review of experience with stage 1 STXS * Development towards a more concrete proposal of stage 2 * Theoretical uncertainties (including correlations) * Residual uncertainties in fiducial and differential cross section measurements * Complementarity between non-standard (SUSY) Higgs searches and precision H measurements * Higgs self coupling * Probing CP violation in the Higgs couplings * What are the holes in the searches for additional non-standard heavy Higgs bosons (H-> tt? what are the possible strategies?) * Searches for very light (ms < mh) scalar particles. Why (theory)? where we are, and where we can be in the future (experiment)? * Exotic decays of the 125 GeV Higgs. Which decay channels are not covered? * Pseudo observables and effective theories * Global picture of naturalness after run1/ first half run2? * Relaxion * High-energy versus high precision in Higgs physics?