Particle Flow Calorimetry

Lead Research Organisation: University of Cambridge
Department Name: Physics


The next accelerator for particle physics experiments after the Large Hadron Collider (LHC) is likely to be a lepton collider, for example the ILC and CLIC. The next generation lepton collider will have the capability to precisely measure the properties of the Higgs boson and other particles expected to be discovered at the LHC. For example, it is not only important to discover the Higgs boson but also to measure precisely its properties like mass and decays modes. These precise measurments will help to establish if the particle found at the LHC is really the Higgs boson of the Standard Model or if it is something else. The detectors at a future lepton collider are being designed to have the required accuracy to perform these measurements. For any physics beyond the Standard Model, for example supersymmetric particles or extra dimensions, there is also a need to have precise measurements of the event properties in order to understand the underlying theory. Most of the decay modes of these particles contain many particles in their final state, clustered together in so-called 'Jets'. The capability to measure the momentum and the energy of these jets is vital to make precise measurements of particle properties. Particle flow calorimetry is a new approach combining the individual strength of both the momentum measurements in the tracking chambers and energy measurements in the calorimeters. Particle flow calorimetry can potentially improve the jet energy resolution by a factor of two compared to more traditional approaches. Particle flow calorimetry requires highly segmented detectors and sophisticated software reconstruction algorthms to utilitise this information. Essentially one attempts relate the energy deposits in all parts of the detector with the particles produced in the collision. This is challenging and requires the development of new techniques to evaluate the potential of particle flow calorimetry. Within the context of the ILC the UK is the worldwide leader in research into this new technique. This proposal aims to develop particle flow calorimetry in a more general sense and to perform and publish the definitive study on this topic. The work would have direct application to the design of next generation collider experiments.


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Abramowicz H (2017) Higgs physics at the CLIC electron-positron linear collider. in The European physical journal. C, Particles and fields

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Linssen, L And Others (2012) CLIC Conceptual Design Report in CERN-2012-003

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Marshall J (2013) Performance of particle flow calorimetry at CLIC in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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Marshall J (2015) The Pandora software development kit for pattern recognition in The European Physical Journal C

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Marshall J (2017) The Pandora multi-algorithm approach to automated pattern recognition in LAr TPC detectors in Journal of Physics: Conference Series

Description Demonstrated the potential advantages to a new technique for measurement of the energies of jets of particles produced in large collider experiments
Exploitation Route The developments are being used by the CMS collaboration in the design of its upgrade to its calorimeter system.

In addition, we have spun out PandoraPFA as a generic pattern recognition framework, which is now being used in neutrino physics. This is the leading reconstruction for the MicroBooNE experiment and DUNE.
Sectors Digital/Communication/Information Technologies (including Software)

Description AIDA-2020
Amount € 172,000 (EUR)
Funding ID RG79119C 
Organisation European Commission 
Department Horizon 2020
Sector Public
Country European Union (EU)
Start 04/2015 
End 03/2020
Description FP7 - AIDA
Amount £76,078 (GBP)
Funding ID RG60700 
Organisation Spanish National Research Council (CSIC) 
Sector Public
Country European Union (EU)
Start 10/2011 
End 09/2015
Description CALICE Collaboration 
Organisation Deutsches Electronen-Synchrotron (DESY)
Country Germany 
Sector Academic/University 
PI Contribution Development of particle flow calorimetry - the concept driving the hardware prototyping within CALICE
Collaborator Contribution Hardware prototyping of high-granular calorimeters
Impact none
Start Year 2008
Description Memorandum of Cooperation with CLIC Physics and Detector Study 
Organisation European Organization for Nuclear Research (CERN)
Country Switzerland 
Sector Public 
PI Contribution Academic research Authorship of publications New knowledge Scientific leadership Executive team member
Collaborator Contribution Access to infrastructure Increased involvement in project
Impact Recently signed, no concrete outputs yet.
Start Year 2013
Description MicroBooNE Collaboration 
Organisation Fermilab - Fermi National Accelerator Laboratory
Department MicroBooNE Experiment
Country United States 
Sector Public 
PI Contribution Software using the PandoraPFA framework is now being used by the MicroBooNE experiment to reconstruct neutrino interactions in data.
Collaborator Contribution Addressed a long-standing challenge with the interpretation of data from LAr-TPC detectors. The output of this research was used for the first results presented by the MicroBooNE collaboration at the Neutrino 2016 conference.
Impact Cross-disiplinary connecting research in collider physics to research in neutrino physics.
Start Year 2015