The ATLAS Experiment at the University of Johannesburg

The High Energy Physics Group at the University of Johannesburg was the first High Energy Experimental Physics group in South Africa to become part of the ATLAS Collaboration at the Large hadron Collider at CERN in Geneva. This was in 2008 via an affiliation with Brookhaven National Laboratory (BNL) in New York, USA. ATLAS is one of two multi-purpose detectors at the LHC, and boasts a collaboration of about 3000 physicists from 39 countries. After two years South Africa became a Member Institution of ATLAS in 2010, where the initial Institutes within SA who joined up were UJ and Wits. The participation of South Africa at CERN more generally has grown and more details can be found the SA-CERN page.

Our Group (2019):
PaNIP - The UJ ATL:AS Group is within a larger group : Particle, Nuclear and Innovation Physics
Group Leader: Simon Connell
Engineer, Computer Scientist : Haydn du Plessis
Staff: Nicolin Govender, Muaaz Bhamjee, Loan Truong
Research Scientist & IT Guru: Sergio Ballestrero
PhD Students: Phineas Ntsoele,
MSc Students: Chris Lee
MSc Students: Xola Mapekula
MSc Students: Mitchell Phiri

UJ-ATLAS in the News:

  1. Sunday Times, 31 August 2008 - The Birth of the Universe
  2. Engineering News, 6 February 2009 - SA scientists’ role in the biggest experiment in the world
  3. Engineering News, 4 July 2012 - SA scientists involved in discovery of new subatomic particle
  4. EWN, 4 Jul 2012 - 'God Particle is groundbreaking'
  5. EWN, 4 Jul 2012 - Simon Connell
  6. News 24, 5 July 2012 - SA prof worked on finding Higgs particle
  7. Tech Central, 6 July 2012 - South Africans in hunt for Higgs
  8. M&G, 6 July 2012 - Locals join the hunt for missing link
  9. Daly Maverick, 5 July 2012 - Higgs boson and the loss of our collective compass
  10. News 24, 4 Dec 2012 - Inside science’s own Big Bang
  11. Engineering News, Large Hadron Collider stimulating intellects and technology, also in South Africa
  12. Polity, 9 Dec 2013 - The growth of science in SA owes much to Mandela – UJ professor
  13. SAIP Physics Comment, 16 Dec 2013 - Prof Simon Connell analyses the influence of Mandela on science in South Africa
  14. IT WEB, 24 Jun 2014 - SA contributes to science breakthrough
  15. Hyper Text, 1 Dec 2014 - INTERVIEW - Meet Claire Lee, a South African ATLAS physicist at CERN
  16. UNISA News, 26 Mar 2018 - PhD student explores deep mysteries of the universe
  17. IT-Online, 29 Aug 2019 - SA researchers super-tune CERN supercomputers - IT-Online

Physics Programme:
Project 1 - The Search for the Dark Force
The UJ group is involved in a search for the force carrier between dark matter candidate particles. It would be a new beyond-the-Standard-Model boson. It uses the Higgs Portal where a Higgs boson with mass 125 GeV decays to four SM leptons (l = e or μ). This decay is presumed to occur via an intermediate state which contains two on-shell, promptly decaying new dark vector bosons: H → ZdZd → 4l. To date, no significant excess of events above Standard Model background predictions is observed; therefore, upper limits at 95% confidence level are set on model-independent fiducial cross-sections, and on the Higgs boson decay branching ratios to vector and pseudoscalar bosons in a benchmark model.
Project 2 - Exotic Invisible Higgs decays.
The UJ group is involved in the search for invisible Higgs boson decays in the vector boson fusion Higgs production mode. This is a search for dark matter using the Higgs-portal dark matter. The invisible branching fraction limit is converted into upper bounds on the dark-matter--nucleon scattering cross section as a function of the dark-matter particle mass, and can be compared to results from the direct dark-matter detection experiments. Once again there is not yet discovery and an upper bound on the H → invisible branching ratio is set.

Physics Analysis:
Analysis of and access to the LHC data is made possible with the new Grid-connected high performance computing cluster at UJ. The Grid is the basis for access to data and the implementation of demanding computational physics analysis.

UJ Research Cluster
The UJ cluster is connected to the European grid and also the US-based Open Science Grid - both of which form part of the worldwide LHC Computing Grid. It is also connected to the South African Computing Grid. The UJ Grid node had seed funding via a collaboration with Jeremy Dodd and Mike Tuts of Columbia University and the OSG team, as well as Ben Clifford from the University of Chicago.
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ATLAS Upgrade
Fiber optic-based sensors for humidity monitoring in the ITK.\\ There is currently no commercially available Rad Hard Humidity Sensor available. This is need for such sensors, for example, for the LHC (and ATLAS, CMS etc), for nuclear medicine, for nuclear energy and for space. Radiation Hard Humidity sensing has been developed by the University Sannio, CERN and some others. The technology is based on a coating on a fibre that alters its transmission properties when humidity is absorbed into the coating, in turn resulting in a strain in the fibre, sensed by interferometry. UJ has undertaken an institute responsibility for the acquisition and deployment of these new Radiation Hard Humidity sensors in the ATLAS Inner Tracker.

UJ is also responsible for the development and maintain ace of the Gui for the DataBase holding information on the configuration of the Muon Detector System, for the Online Control at Point 1, The ATLAS Detector Control Centre at CERN in Geneva.

Technology Transfer
The MinPET project takes advanced technology for fast high granularity detectors, high throughput electronics, high current compact accelerators, high performance computing, artificial intelligence, big data and quantitative machine vision to the mining sector. It implements intelligent, sensor-based sorting of diamondiferous from barren kimberlite. Below is a picture of a kimberlite rock, spiked with a diamond, and a PET reconstruction from our PET detector system which shows the discovery of the diamond within the kimberlite. The image comes from a recent Full Dress Rehearsal at laboratory scale but matching the performance in activation, detection and throughput rate that would correspond in scaling to a run-of-mine scenario of 700 tons per hour. This represents the elusive ability to see into rock and discover a locked diamond with a very high diamond-to-kimberlite volume ratio. The picture is a recent development at the Technology Demonstrator developed by the UJ group at its laboratory at iThemba LABS Gauteng campus. The project now enters an exciting new phase, as it has just found a commercial venture capitalist partner / mine client. This is leading to a R&D Mine Test Unit at a diamond mine, to be integrated as a commercial unit in due course, with a capacity of 400 tons per hour. It will be the first major South African innovation representing commercialization of high end technology and leading to competitive industry resulting in a significant part from the participation in the research programme at CERN. A recent breakthrough has been the use of artificial intelligence techniques to classify the presence of a diamond in the rock, the size of the diamond and also its position co-ordinates related to the speed in belt which is transporting it. This is the first all-machine 3D sensor based sorting of diamond within rock.

More Photos with the ujatlas tag on flickr.