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2.3: Particle Flow Tools

2.3: Particle Flow Tools. Mark Thomson University of Cambridge. Overview. Task 2.3 Work described here from three groups Cambridge PandoraPFA framework algorithm development/optimisation CERN extensive validation performance benchmarking LLR algorithm development.

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2.3: Particle Flow Tools

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  1. 2.3: Particle Flow Tools Mark Thomson University of Cambridge

  2. Overview • Task 2.3 • Work described here from three groups • Cambridge • PandoraPFA framework • algorithm development/optimisation • CERN • extensive validation • performance benchmarking • LLR • algorithm development Mark Thomson

  3. Particle Flow Reminder Mark Thomson

  4. Traditional Calorimetry • In a typical jet : • 60 % of jet energy in charged hadrons • 30 % in photons (mainly from ) • 10 % in neutral hadrons (mainly and ) • Traditional calorimetric approach: • Measure all components of jet energy in ECAL/HCAL ! • ~70 % of energy measured in HCAL: • Intrinsically “poor” HCAL resolution limits jet energy resolution g n p+ EJET = EECAL+EHCAL Mark Thomson

  5. PFlow Paradigm • Particle flow approach: • Try and measure energies of individual particles • Reduce dependence on intrinsically “poor” HCAL resolution • Idealised Particle Flow Calorimetry paradigm: • charged particles measured in tracker (essentially perfectly) • Photons in ECAL: • Neutral hadrons (ONLY) in HCAL • Only 10 % of jet energy from HCAL improved jet energy resolution g n p+ EJET = ETRACK+Eg+ En EJET = EECAL+EHCAL Mark Thomson Mark Thomson

  6. PFlow Paradigm • Particle flow approach: • Try and measure energies of individual particles • Reduce dependence on intrinsically “poor” HCAL resolution • Idealised Particle Flow Calorimetry paradigm: • charged particles measured in tracker (essentially perfectly) • Photons in ECAL: • Neutral hadrons (ONLY) in HCAL • Only 10 % of jet energy from HCAL Complex Pattern Recognition improved jet energy resolution g n p+ EJET = ETRACK+Eg+ En EJET = EECAL+EHCAL Mark Thomson Mark Thomson

  7. PandoraPFA 18 GeV Clustering Topological Association 30 GeV 12 GeV 9 GeV 9 GeV 6 GeV • Such high granularity Pflow reconstruction isnon-trivial ! PandoraPFAinitially developed for “proof of principle” at the ILC HCAL ECAL Iterative Reclustering Fragment ID Photon ID For more details: MT, NIM 611 (2009) 24-40 Mark Thomson

  8. The AIDA Work • PFlow framework - PandoraPFA • PFlow tools Mark Thomson

  9. PandoraPFA • Pandora Software • Originally written in “physicist C++” • Then thrown away…. ~ • Pandora Software Development Kit • 6 – 12 months of careful design • Robust, fast, optimised container choices, etc. • Through AIDA, evolved through new applications ILC CLIC Mark Thomson

  10. PandoraPFA • Development process • Three main steps Redesign Implementation Generalisation Development through multiple use cases Software engineering Coding Mark Thomson

  11. Framework • The new PandoraPFA framework – detector independent Pandora Framework, treat as “black box”: Pandora Algorithms: Client Application: Pandora Content API Pandora API • Highly optimised (CPU/memory footprint) framework • User code “Algorithms” separated from Framework code Mark Thomson

  12. Generic Aspects Designed to be Generic and reusable • Stand-alone library accessed via APIs • “add calorimeter hit” • “add track” • “return particle flow objects” • Framework Aspects • deal with memory management • designed to be compact and very fast • runs Algorithms • supports external plug-ins (via APIs), e.g. algorithms, PID,… • No external dependencies ! • 0 % root inside • No internal use of geometry information • e.g. hits are now self-defining (size, orientation) • Within AIDA also developed internal event display (CERN) “Easily” adaptable to any detector Mark Thomson

  13. LC Use case • PandoraPFAused as workhorse for CLIC CDR (2012) and ILC TDR (2013) • All full simulation physics studies based on PandoraPFA reconstruction ! • Client applications written for two different detector concepts • + variants for CLIC e.g. CLIC CDR Benchmark studies (Cambridge/CERN) published: “Performance of particle flow calorimetry at CLIC”, J.S. Marshall et al., NIM A 700, 2013, 153-162 Mark Thomson

  14. Beyond the LC • New Pandora software designed to be generic • just write the interface (Pandora application) • First non-LC use case… CALICE Mark Thomson

  15. CALICE application • CERN developed client to PandoraPFA for CALICE test beam • e.g. 80 GeV pion test beam • Once client application was written, reco. worked out of the box… • Demonstrated “generic”nature, but this is an LC calorimeter prototype… Mark Thomson

  16. AIDA WorkFar beyond the LC Mark Thomson

  17. Generalisation • Originally PandoraPFA tied to LC detector studies • AIDA re-implementation as a framework • greatly increased flexibility • part of AIDA project aims was to utilise this new flexibility • Now have a number of client apps • 3 separate “content” libraries of algorithms • Fine Granularity calorimetry– e.g. LC detectors • Coarse Granularity calorimetry– e.g. LHC detectors • Liquid Argon reconstruction – Neutrino physics • New use cases, drive new features • New applications making code more general • e.g. no assumptions about geometry • hits can be 2D or 3D (e.g. Liquid Argon TPC) • hits can be shared between clusters (e.g. ATLAS) Mark Thomson

  18. Neutrino Physics • Liquid Argon TPCs likely to form basis • of future neutrino oscillation experiments • Large volume detectors with ~1mm3 granularity • i.e. Fine Granularity calorimeters • Long standing problem • lack of automated reconstruction software • non-trivial – large numbers of hits • applications often run into • memory/CPU limitations Need optimisedframework… PandoraPFA • PandoraPFA framework applied to this problem improved SDK Mark Thomson

  19. e.g. LArSoft Architecture LArSoft LArPandoraInterface art::producer LArSoft framework Pandora Inputs: GeometryService recob::Hits Input Geometry Hits PandoraPFA SDK & Monitoring Pandora APIs Outputs: recob::Clusters Output Reco Particles LArPandoraAlgorithms (LArPandoraAlgorithms: housed within LArSoft, as mirror of SVN). Algorithms Mark Thomson

  20. Recent Developments Work in last 6 months focussed on LAr TPC reconstruction • Many framework improvements • Developed for LAr- but wider applications • Recent highlights: • templating of all internal objects/managers • easy to expand, e.g. new vertex class • Adding of AlgTools • Plug-ins for algorithms • + code re-organisation • ease of maintenance Mark Thomson

  21. Eye Candy • Now being used forMicroBooNE(data this year) and LBNE (b) (a) e+ e- g p- g p0 p+ p+ g p+ p- p p p- 16 GeV ne CC 27 GeV anti-ne CC Mark Thomson

  22. Eye Candy • Now being used forMicroBooNE(data this year) and LBNE (b) (a) e+ e- g Getting close to full reco chain p- g p0 p+ p+ g p+ p- p p p- 16 GeV ne CC 27 GeV anti-ne CC Mark Thomson

  23. PandoraApplicationsc. 2014 Mark Thomson

  24. Pandora Customers • LC Applications: • All ILC physics studies, both ILD and SiD • All CLIC physics studies, both CLIC_ILD and CLIC_SiD • + Linear Collider Detector optimisation • Neutrino Applications: • Strong candidate for MicroBooNE reconstruction • Being developed for LBNE physics studies • + studies for LBNO (Warwick) • LHC/HL-LHC Applications • CMS now have a Pandora application (Athens) • Being investigated for CMS upgrade studies (see later) • + discussions with ATLAS groups AIDA: Pandora generic/reusable framework Mark Thomson

  25. Algorithm Development at LLR Mark Thomson

  26. Papers: Reco. Tools • In Period P1 (reminder) • Development of photon finder: GARLIC • JINST: D. Jeans, J. Brient, and M. Reinhard, “GARLIC: GAmma Reconstruction at a LInear Collider experiment,” JINST 7 (2012) P06003, arXiv:1203.0774 [physics.ins-det]. • development of an event display for PFA (DRUID) • ACAT'11:M. Ruan, “Druid, displaying root module used for linear collider detectors,” in Proceedings ACAT’2011, vol. 368, p. 012040. September, 2011. http://indico.cern.ch/event/93877/ • Fractal dimension of showers as ParticleID and Energy estimators: • ACAT'11: M. Ruan, V. Boudry, J. Brient, D. Jeans, and H. Videau, “Fractal dimension analysis in a highly granular calorimeter,” in Proceedings ACAT’2011, vol. 368, p. 012038. September, 2011. http://indico.cern.ch/event/93877/ • In period P2: • PRL: M. Ruan, D. Jeans, V. Boudry, J.-C. Brient, and H. Videau, “Fractal Dimension of Particle Showers Measured in a Highly Granular Calorimeter,” Phys. Rev. Lett. 112 (Jan, 2014) 012001, arXiv:1312.7662 [physics.ins-det]. http://link.aps.org/doi/10.1103/PhysRevLett.112.012001. • A tree like clustering algorithm for PFA (ARBOR) • CHEF'13M. Ruan, “ARBOR, a new approach of the Particle Flow Algorithm,” in Proceedings, International Conference on Calorimetry for the High Energy Frontier (CHEF 2013), J.-C. Brient, ed. April, 2013. arxiv.org:1403.4784 [physics.ins-det]. http://llr.in2p3.fr/chef2013/index.php Mark Thomson

  27. ARBOR • Topological clustering by connection of hits (cells) & cleaning • Every branch is created (backwards) • Only longest ones are kept • Link branches to trees according to spatial distances • Branch information is kept⇒ track finder e.g. for fitting Mark Thomson

  28. ARBOR • Excellent agreement for track length: • e.g. single gun event at ILD RPC HCAL, compare length: • Charged MCParticle: spatial distance between start & end points • Arbor branch: sum of distance between neighbouring cells Separation: overlay showers Mark Thomson

  29. Fractal Dimensions • New way of classifying showers for PiD based on fractal • dimension • published in PRL MC SDHCAL test beam • Looks promising Mark Thomson

  30. LLR Algorithms • Very promising ideas • Now need to: • integrate into repository • Integrate into PandoraPFA Mark Thomson

  31. CMS-HGCAL Studies SHASHLIK (LYSO) or SILICON –Tungsten • High Granularity Si-W ECAL for the CMS endcapupgrade • Application of PandoraPFA, GARLIC and ARBOR foreseen • this year (part of MS15) • Work has started, e.g. • pp min-bias 140 pile-up: display with DRUID Mark Thomson Vincent.Boudry@in2p3.fr WP2 activities @ LLR 31/6

  32. Conclusions Mark Thomson

  33. Conclusions • AIDA funded Particle Flow Calorimetrywork is progressing well PandoraPFA framework, LC reimplementation, Neutrino physics, real LHC interest LC benchmarking, visualisation, CALICE application e.g. Arbor algorithm + fractal dimensions Milestones & Deliverables: • MS10: month 10 : “Application of prototype PFA for LC” • D2.5 : month 12 : “Software design for PFA” • D2.9 : month 38 :“Particle flow software tools” • MS15: month 44 : “Application of PFA tools to sLHC detectors” Complete Complete Complete In progress Mark Thomson

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