Tau Jet Identification in Higgs Semi-Leptonic Decay channel

FCCAnalysis
1

Hello,

I’ve been working on semi-leptonic decay channels of the Higgs boson at √s = 125 GeV to study the electron Yukawa coupling and the corresponding backgrounds (preliminary study was done by David d’Enterria). For the preselection stage, I selected events with one isolated electron (or muon) and two exclusive jets. I have completed my analysis for these two channels.

However, for the tau decay channel (ee_H_WW*_taunutauqq), I am facing challenges in identifying tau jets effectively. I was wondering if there is any specific method to select these tau jets?

Signal files are located at:
/eos/experiment/fcc/ee/generation/DelphesEvents/winter2023/IDEA/wzp6_ee_Hlnuqq_ecm125/
/eos/experiment/fcc/ee/generation/DelphesEvents/winter2023/IDEA/wzp6_ee_Hqqlnu_ecm125/

Thanks in advance for the help
Apranik

2

Hi @Apranik.F,

what is your current method for identifying tau jets?

Best,
Juraj

1 Like
3

Hi @jsmiesko

Since I’ve never worked with Tau jets before, I started searching for identification algorithms and came across the Tau1P3P algorithm. I tried implementing it but struggled with handling the tracks properly, so that attempt didn’t succeed (and I’m not sure if it was the best choice to begin with). Then I searched through the examples looking for tau-tagging examples , but that only added to my confusion. At this point, I’d appreciate some guidance on where to start and how to approach this effectively.

Info on Tau1P3P is available at page 5 of the following paper : https://cds.cern.ch/record/1045637/files/arXiv:0707.0928.pdf

Kind Regards
Apranik

4

Hi @Apranik.F,

Do you also do your own jet clustering? Or you use jets provided from Delphes?

In FCCee winter2023 pre-generated samples there is the ParticleIDs collection, which already contains TauTag from Delphes. More info here. In order to get this information, you will have to jump from jet to particleID and in the parameters vector, the second element is the TauTag.

Best,
Juraj

1 Like
5

Hi @jsmiesko

I wanted to do both to see the difference, but till I get the hang of the data and more hands on experience, I will stick to the Delphes TauTag. Thanks for the information, I really appreciate it.

Yours Sincerely,
Apranik

1 Like
6

Hi all,

We cannot trust too much the tau collection in Delphes, as the algorithm used is optimized for hadron colliders.

The way to proceed in FCC(-ee) is to use the jet clustering and flavor tagger, which also has a dedicated score to identify tau jets. An example can be found here:

https://hep-fcc.github.io/fcc-tutorials/main/fast-sim-and-analysis/fccanalyses/doc/starterkit/FccFastSimAnalysis/Readme.html#part-ii-produce-a-flat-tree-and-analyse-events

Best,
Jan

1 Like