Question Regarding the Reconstruction of Jets from Displaced Vertices

Asked by Samuel Alipour-fard on 2018-10-07

Dear Madanalysis Team,

I have been performing studies with long lived dark particles which decay to dijets at displaced vertices, and have been running into a bit of an issue with jet reconstruction. So far, I have been using Delphes and ROOT to address my issue, but I was wondering if perhaps there was any existing work involving displaced jets in Madanalysis that I could use to address the issue instead.

In particular, it seems that tracks originating at different displaced vertices often hit the HCAL in similar locations. As a result, the standard jet algorithms identify them as being in the same jet, whereas with the track information it's very obvious by eye that they should not be. Unfortunately, this significantly disrupts my ability to accurately simulate background rates for my search. I have tried using existing capabilities of Delphes to address this issue, but so far I have had no success.

I was looking at the presentation located at, and noticed that on slide 28, it seems like your team is aware of such difficulties involving displaced jets. Though you mention these as possible future developments, I was just curious if any of the work you had in mind might have panned out in the past year. I was also curious if there are any ideas or resources towards this problem that I could test out. The ability to accurately reconstruct jets from displaced vertices would be vastly helpful for my work.
Thanks very much for your time.


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MadAnalysis 5 Edit question
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Solved by:
Benjamin Fuks
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Best Benjamin Fuks (fuks) said : #1

Hi Sam,

We have a version (not yet merged to the main branch) that allows to treat displaced leptons. But we haven't found the time yet to start developing methods for displaced jets. We want to do it, but I can't give you any ETA for now (could be at some point in 2019).



Thanks very much Benjamin. Cheers.