Research at the energy frontier with the ATLAS Detector

  1. Muon Reconstruction with the ATLAS New Small Wheel at the LHC 

    Alain Bellerive, Jesse Heilman, Kevin Graham

    In 2022, the CERN Large Hadron Collider (LHC) beneath the France–Switzerland border near Geneva turned on after a major upgrade that double its delivered instantaneous luminosity. This is an important milestone that follows a very successful two periods of running that saw, among other things, the discovery of the Higgs boson. To cope with the anticipated LHC operating conditions, an extensive overhauling of the detector reconstruction algorithms for ATLAS is underway to reflect the introduction of a new subsystem called the New Small Wheel (NSW). These hardware and software enhancements will allow ATLAS to maintain its capability to perform cutting edge physics studies under the new experimental conditions during 2023/2024 and beyond. The Carleton University ATLAS group was a major contributor to the construction of the recently installed NSW upgrade to the ATLAS endcap muon spectrometer.  The small-Strip Thin Gap Chambers (sTGCs) allow for a much better rejection of fake tracks at the trigger level, as well as improved reconstruction of muon candidates.  Now that the sTGC has been deployed in the ATLAS experimental cavern and the first data from LHC Run3 has started to come in, the NSW needs to be optimized for data mining and validated for physics analyses.

    Interested students will participate in the various aspects of the performance evaluation of the new muon tracking using Monte Carlo simulation and real collision data. The student will be developing advanced patter recognition algorithm for the reconstruction of tracks from hits in the NSW. This will enable the Carleton ATLAS team to be ready for the new 2024 LHC data.  The student selected for this project will be giving the opportunity to be hired as a summer research assistant and be located at CERN during the May-August 2024 period. Students who work on this project will contribute to the development and validation of the muon reconstruction software.  This will require learning the basics of particle physics, particle detector design and operation, and programming skills in ROOT, Python and C++.   

  2. Analysis of ATLAS data

    The Large Hadron Collider just outside Geneva, Switzerland, is delivering high energy proton-proton collisions that are being recorded by the ATLAS detector. During the Run-2 (2015-2018) and Run-3 (presently ongoing) data taking periods, we have collected a very large new dataset of such collisions. Through analysis of this data, we can expand our knowledge of the fundamental nature of our world. One of the topics that will be investigated is studies of the Higgs boson that was discovered in 2012. 

    This summer project involves analysis of the ATLAS data. Possible tasks are to explore kinematic and production properties of the Higgs boson in events where it decays either to two muons or in conjunction with a vector boson such the W or Z bosons. These are very rare Higgs processes which can provide additional handles to probe new physics beyond the Standard Model of Physics. The developed analyses can then expand in preparation for the Run-3 data taking period scheduled for 2022 to provide input for improved statistics and/or observation potential. This work will include working both with Monte Carlo simulated collisions and with the actual LHC data. As part of this project, improvements of the ATLAS reconstruction will be investigated that might aid future discoveries.

  3. Characterization of the electrical properties of silicon sensors for the ATLAS detector upgrade at the LHC

    In 2026-2028, the Large Hadron Collider and the ATLAS detector will undergo major upgrades to prepare for the High Luminosity LHC (HL-LHC) scheduled to start in 2029. The HL-LHC will operate at a significantly higher intensity: the instantaneous luminosity of the proton beams will be seven times that of the design criteria. This significantly enhances the overall physics potential, but also makes the experimental conditions harsher and more challenging. The entire inner tracking detector of ATLAS will need to be replaced with a new silicon Inner Tracker detector (ITk) to cope with this situation. The particle physics group at Carleton University is actively working on this detector upgrade, and is looking for interested students to work on the characterization and performance evaluation of the ITk detector sensors. This work will include the study of the state-of-the-art thin silicon sensors, as well as specially designed test structures that will be probed by dedicated equipment in order to understand their physics performance under carefully controlled environmental conditions. As a separate task, the evaluation of the performance of silicon test structures under high radiation conditions and the study of radiation-induced effects on semiconductor materials, will also be pursued. Both projects will require the development of the required experimental setups, including LabView-based readout and control software, as well as C++-based analysis of the measurement data. In both projects, students will acquire extensive experience in working in clean rooms under environmentally controlled conditions, in handling state-of-the-art experimental equipment, in performing extensive data analysis using ROOT and other software packages and in basic database operations.


For more information on the ATLAS project at Carleton University, please consult


Professor Alain Bellerive (alainb atphysics [dot] carleton [dot] ca)
Professor Dag Gillberg (dag atphysics [dot] carleton [dot] ca)
Professor Kevin Graham (
Professor Jesse Heilman (heilman atphysics [dot] carleton [dot] ca)
Professor Thomas Koffas (koffas atphysics [dot] carleton [dot] ca)






Search Carleton