wiki:Korea2017-02-CMS-EXO-16-012

Version 20 (modified by Jory Sonneveld, 7 years ago) ( diff )

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The first MadAnalysis 5 workshop on LHC recasting @ Korea

Analysis 2: CMS-EXO16-012

Students Yongsoo Jho (Yonsei University), Jiwon Park (Hanyang University), An Seohyun (Hanyang University), Wenxing Zhang (CITP)
Supervisor(s) Guillaume Chalons, Jory Sonneveld

1. Analysis summary

Mono-Higgs.

A search for dark matter is performed using events with large missing transverse momentum and a Higgs boson decaying either to a pair of bottom quarks or to a pair of photons. We are only interested in the photon pair final state. This analysis searches for excesses over the background-only prediction in events with large pTmiss and a diphoton system that has a reconstructed invariant mass close to the mass of the SM-like Higgs boson h.

2. Analysis global information

Selections are based on:

Ref [60] arXiv:1508.07819

http://cms-results.web.cern.ch/cms-results/public-results/publications/HIG-14-016/index.html

Ref [61] arXiv:1407.0558

https://github.com/cms-sw/genproductions/tree/master/python/ThirteenTeV

3. Selection description

3.1 Trigger selection

Diphoton triggers with asymmetric transverse energy thresholds (30/18 GeV) are used to select events with the diphoton invariant mass above 95 GeV. The trigger selection uses a very loose photon identification based on the cluster shower shape and loose isolation requirements and a requirement that the ratio of hadronic-to-electromagnetic energy (H/E) of the photon candidates is less than 0.1.

3.2 Object definition

A global event reconstruction is performed using the particle-flow (PF) algorithm.

  • Jets: Jets are reconstructed from the PF candidates using the anti-kT clustering algorithm with distance parameters of 0.4 (AK4 jet) and 0.8 (AK8 jet), as implemented in the FASTJET package. A pruning algorithm is applied to AK8 jets.
  • Photons: Two categories (the barrel–endcap transition region of 1.44 < |eta| < 1.57, where photon reconstruction is not optimal is excluded)
    • Photons with |eta| < 1.44
    • Photons with 1.566 < |eta| < 2.5
    Photon reconstruction and identification seems very involved (using BDTs).
  • Electrons: The reconstructed electrons must lie within |eta| < 2.5
  • Muons: Muons candidates are required to be within the region |eta| < 2.4
  • Taus: Tau lepton candidates are required to have |eta| < 2.3

3.3 Cut-flow chart

3.4 Definition of exotic observables

None.

4. Detector simulation

Can we use the last release of the Delphes package with the CMS/ATLAS MA5tune-card? or do need to improve the simulation?

5. Validation material

Contact with CMS people established. Waiting for the material

5.1 Monte-Carlo samples

  • LO/NLO? LO
  • Model used: Z′-2HDM
  • MC generator program (name + version): MADGRAPH5 aMC@NLO v2.3.0
  • Shower program (name + version): PYTHIA 8.205
  • Tune of Pythia: CUETP8M1
  • PDF set: NNPDF 3.0
  • ME/PS merging???? MLM

5.2 Reference plots / cut-flows

  • List of validation material

6. Validation results

7. Reinterpretation (optional)

8. Questions / issues

9. Analysis People Contact

  • Jory Sonneveld: [mail: jory@opmijnfiets.nl]
  • Guillaume Chalons: [mail:guillaume.chalons@th.u-psud.fr]
  • Yongsoo Jho: [mail:1jys34@gmail.com]
  • Jiwon Park: [mail:minerva1993@gmail.com]
  • Seohyun An: [mail: klar.wind0425@gmail.com]
  • Wenxing Zhang: [mail: zhangwenxing@itp.ac.cn]
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