Experimental Particle Physics F9


Research departments
Administration and support units


Departmental research is devoted to experimental studies of elementary particles, to reveal the ultimate building blocks of matter and the nature of the interactions between them. Experiments are carried out within large collaborative programmes at international centres for particle physics at CERN near Geneva and at KEK in Tsukuba. The Department is also engaged in developing and applying the technologically advanced particle detectors, which are demanded by such measurements. Astroparticle physics is an emerging field applying experimental techniques of particle physics to solve astrophysical problems. Slovenian researchers are participating in measurements of ultra-high-energy cosmic rays with the Pierre Auger observatory spread over a surface of 3000 km2 near Malargue in Argentina.


  • ATLAS at the Large Hadron Collider (LHC) at CERN
  • Belle and Belle II at the asymmetric electron-positron collider at KEK
  • Pierre Auger observatory
  • Distributed computing
  • Detector development

Departmental web pages

Head of Department
Prof. Marko Mikuž, Ph. D., marko.mikuz@ijs.si

Andreja Butina, Andreja.Butina@ijs.si
Telephone: +386 1 477 37 42

Experiment ATLAS at LHC studies processes occurring at collisions of protons with energy of 13 TeV and tests the predictions of the Standard Model like the existence of Higgs boson proven by the experiments at the LHC. Equally important are searches for processes which would points toward new physics, not described by the Standard Model. In the ATLAS experiment researchers from the department F9 are involved in maintenance and operations of detector system during data taking and in analysis of collected data.

Experiments Belle and Belle II, operating at the electron positron collider KEKB / SuperKEKB in Tsukuba, Japan, belong to the group of the so-called intensity frontier experiments in the experimental particle physics. The aim of such experiments is a search for processes and particles not included in the Standard Model (SM), commonly addressed as New Physics (NP). To do so, extremely precise measurement results are confronted to predictions of the SM. While the latter is considered as a very successful effective theory, it is believed that NP must exists and is responsible – among else – for the observed matter – antimatter asymmetry in the universe.

The Pierre Auger Observatory detects ultra-high-energy cosmic rays with energies beyond 1018 eV. In Earth's atmosphere such particles form shower of secondary particles. Properties of primary particles like energy, arrival direction and the particle type can be estimated from the shower. High energy particles are very rare therefore the detectors of the Observatory are installed over a huge detection area of 3000 km2 located in the western Mendoza Province, Argentina.

The distributed computing centre is mostly dedicated to simulation and reconstruction of data produced with the ATLAS detector and for Monte-Carlo simulation of the Belle II detector. The computing resources of SiGNET Tier-2 are 6500 CPU cores and 4.PB of storage space while the throughput of the international link to LHCONE network was 30Gb/s in 2017. General purpose NSC cluster at Jožef Stefan Institute and computing centre of ARNES are transparently included in distributed computing infrastructure within WLCG collaboration and EGI infrastructure. The system enables job submission to Slovenian computing centre and a quick processing of 100 TB data in few hours.

Detector development is oriented in several directions: silicon monolithic CMS detectors, detectors with few tens of picoseconds timing resolution and diamond detectors for operation in high radiation environments in hadron collider experiments. Another direction is development of detectors for Cherenkov photons for Belle II and high precision timing detectors for medical imaging. Development of detectors for annihilation photons for PET and development of system for multichannel readout of micro-dosimeters are also devoted to applications in medicine.

J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Telephone: +386 1 477 39 00