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Les Houches

2021 Session

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Les Houches Themes



SMEFT analysis of high-pT dilepton tails, including angular observables

Participants Aoife Bharucha, Dario Buttazzo, Juhi Dutta, Berni Gaud, Tetiana Hrynova, David Marzocca, Marco Nardecchia, Giacomo Polesello, Priscilla Pani, Minho Son, Elena Venturi, Natascia Vignaroli, Tevong You, Adam Falkowski


Preliminary proceedings note: PDF

To do:

  • (Done) Validate our UFO against other codes (e.g. SMEFTsim) (Elena and Jordan)
  • (Done) List the parameter points required to build the complete EFT dependence of the signal
  • (Done) Clarify the required simulations (only parton level, or also showering) for the 8TeV analysis [1606.01736], which shows double-differential cross sections at the Born level (in QED). (Dario, Juhi, Natascia)
  • Fix details of the simulations (David, Juhi)
  • Run the simulations for the benchmark points (38 points)
  • Construct the quadratic dependence on the EFT coefficients in all the bins.
  • Build the global likelihood and derive the fit: 1) linear vs. quadratic, 2) including angular distributions vs. not including.
  • Consider 13 TeV data
  • Consider p p > l nu (limits on the triplet operators) and either study sensitivity prospects or recast data


  • Jordan Bernigaud -
  • Aoife Bharucha -
  • Dario Buttazzo -
  • Juhi Dutta -
  • Adam Falkowski -
  • Tetiana Hrynova -
  • David Marzocca - (contact person)
  • Priscilla Pani -
  • Giacomo Polesello -
  • Minho Son -
  • Elena Venturini -
  • Natascia Vignaroli -
  • Tevong You -

Other topics for consideration

  • LFV dsigma(pp>mutau)/dm
  • Improving sensitivity on operators with b-quarks in high-pT mu-mu, tau-tau, tau-nu tails with b-tagging.
  • pp → llq: Adam, Natascia, Aoife

Summary of the meeting 8/11/2019

After a recap of the project and what was done during the Les Houches workshop, we discussed the next steps to take and divided the various tasks. The goal of the project and the general strategy is sketched in the notes, together with some other relevant details. In short, we want to put limits on SMEFT operators from the 8TeV ATLAS double-differential distribution, and check the difference to the limits obtained using only the single distribution in m_ll. We already have a working FeynRules UFO model which includes all the dimension-6 operators we are interested in. Short-term tasks (and people who self-assigned to them) with a timeline of 1-2 weeks:

  1. Validation of the UFO against SMEFTsim (Elena and Jordan)
  2. Check the effect of the parton shower (QCD) on the BSM-dependence of the cross section in the bins we are interested in (high invariant mass): do we need to shower or not? (Juhi, Natascia, David)
  3. Fix the details of the simulation: cuts, bins, etc. (David, Juhi)

Once these things are done we can proceed with the event generation for all the 38 parameter space points listed in Table 1 of the notes. We will divide the simulations jobs among us.

2019/groups/bsm/lfv.txt · Last modified: 2019/11/28 14:54 by david.marzocca