Liverpool DiPhoton Group

In order to co-ordinate the groups diphoton activities, a mini group (Helen Hayward, Steve Maxfield and Barry King) has been formed to collaborate on various (di)photon activities with the aim of making an impact in GMSB and exotic diphoton searches


  • Finish Susy Csc08 note (link to atlas gmsb twiki page) - Helen editor of non-pointing section
  • comparison of various diphoton generators - Barry contributing to dilepton/diphoton note
    • Steve to chase Samir for names of generators
  • single particle gun, neutralino in full sim ?
  • Look into improving reconstruction/identification of nonpointing photons : barry
  • write talk on fate rate Trash/CDF history and plans - Helen's talk to dilepton/diphoton group.
  • investigate possible Fqcd methods at ATLAS ?
    • conversions
    • presampler - limited depth, depth varies with eta
    • 1st sampling layer.... analyse shower profile
    • isolation
  • Meet with Daniel F - Helen and Barry 24th Feb.
    • What is the H->gammagamma presampler method ??
  • Is there a clever way to combine Zprime and timing info for neutralino lifetime extraction ? - Steve ?
  • Can we use conversion probability to estimate distance travelled ?
  • Can we estimate energy of neutralino somehow ?

Choice of Analysis Framework

suggestions + links:


  • Meeting with Daniel Froideveaux 24th Feb (H+B)

    • concentrate on seperating pi0 and photons, 4 possible methods: conversions, presampler, 1st sampling (shower profile) and isolation
    • in v13, only etcone20 is present - more choice in v14, but we should ask for it to make sure.
    • There will be a group effort at cern looking at fakes (guiliamme unal)
    • DF asks whether we can do this work under the umbrella of the egamma group.
    • in version 13, the reclustering of egamma objects on the AOD has not been validated... photon clustering uses 5x9. also hits on trackes available.

Helen's notes

  • Multivariate analysis for neutralino lifetime

Steve's notes

On Fake Rates

Here are links to some recent talks etc. on fake rate estimation.

  • Talk given at November 07 Trigger and Physics Week to the Higgs working group:
  • Almost nothing at higher Pt. this from October 23rd CSC exotics Dilepton/Diphoton meeting:
  • The CSC note covering this from the exotics perspective is here:
  • Available single particle datsets are located :

Diphoton generators etc.

* The DIPHOX home page can be found : here * ...and RESBOS: here

The comparison of RESBOS and DIPHOX generators, again in the lower energy context of H->GammaGamma was discussed in this talk from the November T&P week:

Here are some papers referenced in the above talk:

Barry's notes

-- HelenHayward - 14 Jan 2008
Topic attachments
I Attachment Action Size Date Who Comment
DilepDiphot.pdfpdf DilepDiphot.pdf manage 1 MB 15 Jan 2008 - 13:56 SteveMaxfield Dilepton-Diphton CSC note as of Jan 15th 2007
Diphotonproductionat_lhc_0306130v1.pdfpdf Diphotonproductionat_lhc_0306130v1.pdf manage 129 K 14 Jan 2008 - 17:22 SteveMaxfield Diphoton production at the LHC (2003)
DiphoxStudy.pptxpptx DiphoxStudy.pptx manage 903 K 15 Feb 2008 - 10:38 SteveMaxfield sjmdiphoxliverpool150208
NLOdirectphotons_binith_et_al_9911340v3.pdfpdf NLOdirectphotons_binith_et_al_9911340v3.pdf manage 779 K 14 Jan 2008 - 17:20 SteveMaxfield DIPHOX paper
Resbosdiphox_0704.0001v2.pdfpdf Resbosdiphox_0704.0001v2.pdf manage 1 MB 14 Jan 2008 - 17:19 SteveMaxfield Resbos Diphox Compared
Topic revision: r11 - 18 Oct 2012, JohnBland
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