Minutes of the LHCHXS WG1 meeting - 08/10/2018

Attending:

• WG1 Paolo (ATLAS), Giovanni (ATLAS), Alicia (CMS), John Campbell

• ggF: Andrea Massironi (CMS), Bernhard Mistlberger (TH)

• VBF: Claudia Bertella (ATLAS), Alexander Karlberg (TH)

• VH: Carlo Pandini (ATLAS), Chris Palmer (CMS), Francesco Tramontano (TH)

• ttH: Maria Moreno Llacer (ATLAS), Stefano Pozzorini (TH), Laura Reina (TH)

• off shell: Roberto Di Nardo (ATLAS) Nikolas Kauer (TH)

Reminder about WS structure:

• plenary sessions for each WG to report its recent activities/results

• parallel sessions in which each WG can define a topic of common interest for the various subgroups that could be useful to discuss all together

• WG1 plenary slot: Monday 10/12 9:00-13:00 (no break?)

• Discussion slot: Tuesday 11/12 9:00-11:30

• Important note: speakers are requested to be at CERN

=> today’s plan: feedback on latest activities, planned talks for workshop, planned meetings before the workshop, and suggestions for common topics (parton shower?)

ggF:

• 27 TeV note in preparation (results already presented)

• note on boosted Higgs searches in preparation, doing final polishing. NNLO QCD predictions with heavy-quark effective field theory.

• note on STXS systematic uncertainties: should ping Kathrin and Dag

• for workshop:

  • Probably 1 overview talk, 20’

  • Planning some discussion before the WS: ???

  • Common topic for discussion: harmonise UE/PS prescriptions among experiments/theory

VBF:

• Have computed xsections with NNLO QCD and NLO EW for high-energy report

• Ongoing: high-pT boosted-Higgs studies, include also high-order corrections. will be done in few weeks.

• small study of PS effects on VBF. Very likely will have some results for December meeting

• STXS: have started to extract uncertainties and to compare numbers to what is used by ATLAS/CMS. Hope to have this in time for the workshop and then documentation written for ATLAS and CMS.

• for workshop:

  • either 1 long overview talk or two shorter talks (one on calculations, one on STXS)

  • Planning one meeting early/mid November

  • Common topic for discussion: OK for UE/PS

VH:

• STXS: work by ATLAS people to compute theory uncertainties. Plan to organise a private meeting with WG2 conveners to discuss approach/numbers, so no need to approve ATLAS numbers for the time being. Carlo will write to them today.

  • is there some feedback already from the theory community? Not yet.

  • anybody in CMS also looking at this? Not yet, maybe by December

• Modelling: work ongoing on

  • V+HF modelling (bkg for VH, H->bb)

  • gg->ZH predictions

  • Rivet analysis implemented, will do some internal review with analysis team and then send to theorists. planning an open meeting around end of October

• High-lumi/high-energy calculations: reviewing document with numbers

• for workshop:

  • maybe 1 theory + 1 experimental talk (recent VHbb observations by ATLAS and CMS)

  • possibly one extra meeting of the subgroup before WS to discuss recent ATLAS and CMS VHbb analyses

  • Common topic for discussion: UE/PS. Perhaps have a meeting before the workshop to discuss together the questions for the theorists. Should be done as soon as possible.

ttH:

• Subgroup focusing on backgrounds

  • tt+bb: scale uncertainties, tensions between MCs ; NLO tt+bb+1jet => 1st internal meeting planned on Oct 22nd

  • ttW, ttZ backgrounds: tension for ttW between experiments/theory => 1st internal meeting on Oct 29th among conveners

  • after these kick-off meeting, weekly subgroup meetings. Plan to have results in December workshop.

• for workshop:

  • 1 theory + 1 experimental talk (recent ttH observation by ATLAS and CMS)

  • common item for discussion in parallel session: OK for UE/PS

Off-shell:

• last meeting in May, not much activity since then, will try to do some progress in time for December

• for workshop:

  • 1 theory + 1 experimental talk (recent ATLAS and CMS papers on off-shell)

  • no meeting planned between now and December

TODO: organize a meeting by end of October to finalise workshop schedule and also discuss in more detail the format of the parallel session