====== Simplified Template Cross Sections (STXS) and EFT constraints ======

People interested (add your name): Francesco Riva, Ken Mimasu, Fabio Maltoni, Benjamin Fuks, Kristin Lohwasser, Jorge de Blas, Pasquale Musella, Alexandra Carvalho, Caterina Vernieri, Benjamin Freund, Adam Falkowski

Perform a case study of the constraining power on EFT Wilson coefficients from Higgs data through STXS.
Compare the sensitivity of performing a fit to the Wilson coefficients of interest via the STXS with a direct fit from LHC data and quantify any loss of information incurred. 

[[https://github.com/musella/LHStxsVsEft|Github repository]]

=== Processes of interest: ===
  * Associated production (VH->bb)
  * Vector Boson Fusion (VBF->gamma gamma, tau tau, ...)

=== Workflow ===

{{:2017:groups:higgs:stxeftworkflow.png?400|{{:2017:groups:higgs:stxeftworkflow.png?400|}}

=== Tasks ===
  - Generate signal and background processes (Ken, Jorge)
  - Modify madanalysis to smear jets and output csv file (Benjamin)
  - Define selection cuts (Caterina and Kristin)
  - Develop RooFit-based stat analysis (Kristin)
  - Prepare skeleton for BDT training (Pasquale) 

=== Samples to generate ===
   * Baseline: 
      * 500k events / process
      * 4-5 EFT points (start with 1-2)
   * VH(bb): SM Z(ll)H, EFT Z(ll)H, SM Z(ll)bb (100<mbb<150)
   * VBF(tau tau): SM VBF, EFT VBF, SM Z(tau tau)
   * EFT operators to probe: OHW (SILH), more?

=== Selection cuts and smearing === 

== ZH->bbar ==

References  
https://cds.cern.ch/record/2206813/files/ATLAS-CONF-2016-091.pdf?version=1
https://journals.aps.org/prd/abstract/10.1103/PhysRevD.89.012003

Selections: 
   * leptons > 25 GeV ,|eta|<2.5 
   * bjets, |eta| < 2.5, pT>20
   * Z mass window --> 75 - 105
   * ptV>0 GeV
 

== VBS Htautau ==

References:
https://cds.cern.ch/record/2264522/files/HIG-16-043-pas.pdf

Selections: 
   * Exactly 2 jets > 30 gev
   * mjj>300 GeV
   * detajj>2.5
   * [((vectorial sum pT taus+met > 50 GeV (lep) / > 100 GeV (had) )) - Note: would probably leave it out?]
   * pT (tau) >30 GeV coming from 
         * tau_had: >50 / >40 
         * lep-had: >20 (26e) / > 30 (had)
         * lep-lep: 13(e)/24(m) / 24(e) / 15(m) 


== Smearings ==
   * CMS particle flow Jet resolution -> https://arxiv.org/pdf/1706.04965.pdf
   * ATLAS resolution on taus: http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/PERF-2013-06


=== Available UFO models: ===
  * HEL at LO (extensive set of SILH basis operators) [[http://feynrules.irmp.ucl.ac.be/wiki/HEL|(link)]]
  * HEL at NLO (small subset of SILH basis operators relevant for EW production) [[http://feynrules.irmp.ucl.ac.be/wiki/HELatNLO|(link)]]

=== References: ===
  * Session 1 STXS page. [[https://phystev.cnrs.fr/wiki/2017:groups:higgs:stxs| (link) ]]
  * Rivet tool implementing stage 1 and 0 selections maintained by LHCHXSWG [[https://svnweb.cern.ch/cern/wsvn/lhchiggsxs/repository/TemplateXS/| (link)]]