Preparation of DAS long exercises

Tuesday 15 Jul 2025, 11:00 → 13:00 Europe/Berlin

SR 4a/b

https://cern.zoom.us/j/64087077370?pwd=bX5hTzCoYEwMnTsUaT4MX0JPxwnn8l.1

General points:

• Please focus on Run 3 if you can

• Test test test! (ask summer students to test?)

• How much space do you need?

• At least for long exercises: make sure the space is used well, like installing one thing in one place and another thing in another space. No 100 GB AFS space available for participants :)

• docs.cern.ch (md) instruction pages very useful for the exercises and for documentation for later usage. If interested, you can contact the TOP exercise facilitators Evan and Dominic

 

For the timetable:

• Consider cut-off for the long exercises with deadline to upload slides, give time to practice slides → important for facilitators to mind giving the students enough time to prepare the talk

 

Inclusive jets (SMP) - Patrick Connor

• 1 TB EOS account more than enough

• Short exercise on unfolding is combine-based rather than TUnfold, so yes, please cover TUnfold as part of your long exercise

• All 3 options for exercise are fine with us. Practically: choose the one that’s easiest to find a co-facilitator

• No other 2D cross section measurement, so that might be good to choose

•  

 

Ttbar cross section (TOP) - Evan Ranken and Dominic Stafford

• Could recruit a 3rd facilitator once we know how many participants for the exercise (would want if > 6 participants)

• Exercise-specific pre-exercise: not essential if done before, but helpful if done

• Need to give them the list of participants for this exercise well in advance of DAS starting

• Uses pepper, runs on nanoAOD

• Includes combine component (doesn’t matter if not everyone has seen combine in short exercise)

• Add to pre-exercises: request extensions on space

• Ask O&C about 2025 DAS directory for big exercise files. Only facilitators have write access?

 

Higgs to 4 leptons (HIG) - Daniel Savoiu, Matteo Bonanomi

• Setting it up on lxplus

• Prerequisite: grid certificate

 

Displaced search (EXO) - Jeremi Niedziela

• First time for this exercise

• Based on the TEA framework (loops, c++ and python)

• Runs over LLPnanoAOD

• Would be useful to use data in ABCD (other long exercises may not use)

• Would be good also for later documentation for ABCD: use EXO methods forum docs

• Should have combine limits, central corrections, (more optionally: muons and jets) short exercises as prerequisite

• Other facilitators? Jeremi will look

• Good to inject signal into data 🙂

 

Anomaly detection (EXO) - Karim?

 

Dark matter (EXO/NPS) - Danyer Perez Adan

• Will prepare monojet analysis exercise from 2024, it was well documented

• Can look for facilitator from DESY, but not a problem if we don’t find one since it’s his own framework. Dominic? Mostly need someone in the room, rather than on the technical side

• Will use his own framework based on c++

• AFS for setting up scripts and submitting jobs, storage on EOS

• Either use samples from 2024 school or use 2016 Open Data on EOS

• Conclusion from meeting: don’t use Open Data

• Grid access is prerequisite

• Dependent on MET. need short exercise on MET or ask Andreas if he can include something on MET in the jet exercise. Or could be part of this long exercise

 

**write down: max of 3 short exercises per participant

 

• Add a facilitators mattermost channel

 

Next meeting: late august

11:00 → 11:10 Introduction

Speakers: Alexander Grohsjean (CMS - University of Hamburg), Alexander Grohsjean (University of Hamburg), Juliette Alimena (CMS (CMS Fachgruppe Searches)), Maria Aldaya Martin (CMS (CMS Fachgruppe TOP)), Matthias Schroeder (Universität Hamburg)

CMSDAS_news_15July2025.pdf

11:10 → 11:15 Inclusive jets (SMP)

Speaker: Patrick Connor (UNI/EXP (Uni Hamburg, Institut fur Experimentalphysik) & CDCS)

3 options:
- inclusive jet 2D cross section measurement (already given three times: DAS18, DAS19, PODAS23)
- $Z\to\mu\mu\gamma$ branching fraction (PODAS23, DAS24)
- Drell-Yan 2D cross section measurement (not yet done, but all pieces are there).

The final choice will also depend on the co-facilitator (still TBD).

In all three cases, the idea is to perform an analysis step by step:
- apply event-level and object-level corrections (and check the jet or muon response before / after corrections)
- understand the basics of unfolding (a priori with TUnfold)
- compare to theory predictions (e.g. NNLOJET with EW and NP corrections for inclusive jet)

Questions from my side:
1. Is there a short exercise on unfolding?
2. Is there a short exercise on jet or muon energy corrections?

11:15 → 11:20 ttbar cross section (TOP)

Speakers: Dominic Stafford (CMS (CMS Fachgruppe Searches)), Evan Ranken (CMS (CMS Fachgruppe TOP))

CMSDAS24_intro.pdf

DAS25 overview

DAS_25_overview.pdf

11:20 → 11:25 Higgs to 4 leptons (HIG)

Speakers: Daniel Savoiu (UNI/EXP (Uni Hamburg, Institut fur Experimentalphysik)), Matteo Bonanomi (UNI/EXP (Uni Hamburg, Institut fur Experimentalphysik))

hig_exercise_physics.pdf

hig_exercise_technical.pdf

LongExercise_Info.pdf

The goal of the exercise is to implement events selection to reproduce the Higgs to four lepton analysis done by CMS.

We use a state of the art columnar-based framework (columnflow) and start from a skeleton that shows the students the selections implemented on electrons and we guide them to the implementation of selections on muons, reconstruction of Z candidates, and eventually ZZ events.

As a final goal, the students will have to plot the invariant mass of the four-leptons system and additional kinematic properties that are relevant for a possible physics analysis.

The exercise builds on the positive experience of the PODAS 23.

TBC: If there is enough time (there wasn't last time, so we won't promise this in advance to the students) we can show them how to perform an actual measurement to extract some properties (Eg xsec) of the H(4l) system.

11:25 → 11:30 Displaced search (EXO)

Speaker: Jeremi Niedziela (DESY)

das_2025_tea_exercise.pdf

11:30 → 11:35 Anomaly detection (EXO)

11:35 → 11:40 Dark matter (EXO/NPS)

Speaker: Danyer Perez Adan (RWTH Aachen)