Mitigation of pileup effects at the LHC

16 May 2014, 08:00 → 18 May 2014, 18:30 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

Ariel Gustavo Schwartzman (SLAC National Accelerator Laboratory (US)), Filip Moortgat (CERN), Gavin Salam (CERN)

Pileup is one of the limiting factors in many LHC studies and the experiments’ ability to control its adverse effects can even affect decisions on machine running.

The purpose of this workshop is to bring together the community of people with experience in pileup mitigation at the LHC, in order to foster exchanges on a range of new ideas that are currently emerging in the field.

Topics to be covered include

• generic jet use, i.e. correcting jet transverse momenta and suppression of pileup jets
• advanced jet use, correcting shapes and masses and groomers/taggers
• questions such as whether to correct whole jet observables (pt, mass), the particle within a jet, or even attempt event-wide PU correction
• interplay of these questions with different experimental jet reconstruction methods (detector effects, topoclustering and particle flow, detector noise suppression, etc.)
• pileup in contexts beyond jets, such as lepton & photon isolation and missing transverse energy measurements
• how best to perform comparisons between different experiments and with theorists’ studies

The workshop will include ample hands-on sessions for trying out and sharing PU mitigation code and results, using standalone simulations and code.

It will run over a long weekend, from the morning of Friday May 16th until late afternoon on Sunday May 18th.
 

There is a mailing list for follow up work: lpcc-pu-mitigation@cern.ch
 

 

software Wiki page

Friday, 16 May

New PU removal techniques

Conveners: Michael Begel (Brookhaven National Laboratory (US)), Philip Coleman Harris (CERN)

1 Introduction

Speakers: Ariel Gustavo Schwartzman (SLAC National Accelerator Laboratory (US)), Filip Moortgat (CERN), Gavin Salam (CERN)

Slides PU_Intro.pdf

2 Jet-Vertex Tagging and track-based grooming

Speaker: Pascal Nef (SLAC National Accelerator Laboratory (US))

Slides 20140516_ATLASPileupJetSuppression_Pascal.pdf

3 NpC

Speaker: Matteo Cacciari (LPTHE Paris)

Slides npc-matteo.pdf

10:45 Coffee

4 Constituent subtraction

Speaker: Peter Berta (Charles University (CZ))

Slides ConstitunetSubtraction_PeterBerta_16.5.2014.pdf

5 Puppi

Speaker: Nhan Viet Tran (Fermi National Accelerator Lab. (US))

Slides puppi_puwksp.pdf

6 Soft Killer

Speaker: Gregory Soyez (CEA/IRFU,Centre d'etude de Saclay Gif-sur-Yvette (FR))

Slides talk.pdf

13:00 Lunch

Software introduction

Conveners: Gavin Salam (CERN), Gregory Soyez (CEA/IRFU,Centre d'etude de Saclay Gif-sur-Yvette (FR)), Matteo Cacciari (LPTHE Jussieu), Nhan Viet Tran (Fermi National Accelerator Lab. (US)), Pascal Nef (SLAC National Accelerator Laboratory (US))

7 Suggested studies and figures of merit

Speakers: Ariel Gustavo Schwartzman (SLAC National Accelerator Laboratory (US)), Gavin Salam (CERN), Gregory Soyez (CEA/IRFU,Centre d'etude de Saclay Gif-sur-Yvette (FR)), Matteo Cacciari (LPTHE Paris)

Slides work.pdf

Work time

19:30 Dinner

Saturday, 17 May

PU suppression techniques

Conveners: Matteo Cacciari (LPTHE Paris), Mikko Voutilainen (University of Helsinki (FI)), Nhan Viet Tran (Fermi National Accelerator Lab. (US))

8 Topoclustering pileup suppression

Speaker: Peter Loch (University of Arizona (US))

Slides ToposLoch.pdf

9 JetID at CMS

Speaker: Philip Coleman Harris (CERN)

Slides PCH_JetID_18_05.pdf

10 Heavy ion PU removal methods

Speakers: Yue Shi Lai (Massachusetts Inst. of Technology (US)), Yue Shi Lai (Massachusetts Inst. of Technology (US))

Slides pu-20140517.pdf

10:30 Coffee

11 Jet reclustering

Speaker: Maximilian J Swiatlowski (SLAC National Accelerator Laboratory (US))

Slides swiatlow_reclustering.pdf

12 Cleansing

Speaker: Matthew Schwartz (Harvard University)

Slides CleansingCERN-Schwartz.pdf

Work time

13:00 Lunch

Work time

Conveners: Michael Begel (Brookhaven National Laboratory (US)), Mikko Voutilainen (University of Helsinki (FI))

13 ATLAS & CMS Pileup Discussion

Speakers: Michael Begel (Brookhaven National Laboratory (US)), Mikko Voutilainen (University of Helsinki (FI))

Slides ATLAS_CMS_PUdiscussion.rtf

Sunday, 18 May

PU mitigation techniques for missing ET

Convener: Matthew Schwartz (Harvard University)

14 Missing ET at ATLAS

Speaker: Peter Loch (University of Arizona (US))

Slides METLoch.pdf

15 Missing ET at CMS

Speaker: Matthieu Pierre Marionneau (University of Maryland (US))

Transparents METCMSPUMWC_051814.pdf

10:30 Coffee

Work time

13:00 Lunch

Work time

15:30 Coffee

Working group reports

16 report

Speakers: Gavin Salam (CERN), Gregory Soyez (CEA/IRFU,Centre d'etude de Saclay Gif-sur-Yvette (FR)), Matteo Cacciari (LPTHE Paris)

Slides all_ovd-summary.pdf

17 report

Speaker: Maximilian J Swiatlowski (SLAC National Accelerator Laboratory (US))

Slides

• Workhop21_100.pdf
• Workhop21.pdf
• Workhop32_100.pdf
• Workhop32.pdf

18 report

Speakers: Matthew Low (University of Chicago (US)), Nhan Viet Tran (Fermi National Accelerator Lab. (US)), Philip Coleman Harris (CERN)

Slides

• mitigation_mass.pdf
• mitigation_pt.pdf
• puppi_results.pdf

19 report

Speaker: Pascal Nef (SLAC National Accelerator Laboratory (US))

Slides JetCleansing_report.pdf JetCleansing_report_update.pdf

20 report

Speaker: Peter Berta (Charles University (CZ))