FCC-ee Physics Performance meeting -

Monday 21 Sept 2020, 15:00 → 17:00 Europe/Zurich

Emmanuel Francois Perez (CERN), Patrizia Azzi (INFN Padova (IT))

CONNECTION WILL BE USING ZOOM. INSTRUCTIONS BELOW

**NO PHYSICAL ROOM** 

zoom-details.txt

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Physics Performance meeting,  Sep 21, 2020

https://indico.cern.ch/event/956147/

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===    Loukas Gouskos, Michele Selvaggi : Jet Flavour Tagging

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In e+e-, a tagger using only low-level information may not be the best.

High-level information should help.

-> compare with the performance obtained with the algorithms used at LC,

eg LCFIPlus, which uses vertexing as part of the jet finding

cf also CEPC Workshop April 2019 (Oxford) [talk of Yao]: PID, jet charge, vertex

mass are examples of useful variables

 

Performances for the CLD detector, obtained with LCFIPlus, shown in

the CLD document [ arXiv:1911.12230 ]

- were done in full Sim (Z events)

Note that for later, with Full Sim: important to have a good rejection of

secondary interactions (as they lead to tracks with large impact parameters).

 

Comment that LCFI+ is not easy to run.

Post-meeting note [ Gerri ] : interfacing with FCCSW will go via the Marlin wrappers in

key4Hep. Not feasible within the current FCCSW.

 

Comment that performances are likely to depend on the jet algorithm, the

parton shower algo etc. And of the sample (kinematics) of course.

 

 

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===   Jeremy Andrea : Plans for ttbart studies

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In contact with Whizard authors for a recipe to properly generate bbWW events

and reproduce the ttbar threshold.

 

Comment about Delphes simulations: instead of producing a large number of samples,

corresponding to many variations of resolutions etc., could add some smearing to

the events from a reduced set of samples.

 

Treatment of beam energy spectrum more simple at FCC than at LC.

Should have a common way (across generators) to model the beam energy spectrum.

Along the same line: a common module is needed that will boost the generated

events, to account for the crossing angle.

 

Sensitivity to anomalous EWK couplings: in addition to lepton energies and angles,

should use other variables, e.g. b jets (need good tagging) or forward-backward ttbar

asymetries.

 

 

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===   Donal Hill : Z-pole flavour physics

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Analysis fully within FCCSW.

 

Candidate building using the "awkward array" python library (expert: Jim Pivarski)

to perform the particles combinations. Will be very useful for other analyses too (e.g. tau ID).

Example to be shared, and candidate building can be integrated in FCCSW

when production ready.

1 News / welcome

Speakers: Emmanuel Francois Perez (CERN), Patrizia Azzi (INFN Padova (IT))

2020_09_21_PP_News.pdf

2 Progress with c-tagging

Speakers: Loukas Gouskos (CERN), Michele Selvaggi (CERN)

lg-fccee-flvtagging_20200921.pdf

3 Plans for t-tbar studies

Speaker: Jeremy Andrea (Centre National de la Recherche Scientifique (FR))

ttbar_snowmass_plan.pdf

4 Z-pole flavour physics at FCC-ee

Speaker: Donal Hill (University of Oxford (GB))

FCC_ee_PP_meeting_21_9_20.pdf

5 Discussion (all): experience / feedback on the common software