ATLAS – Niels Bohr Institute - University of Copenhagen

Experimental Particle Physics – ATLAS

The research group HEP (High Energy Physics) works with ATLAS experiments that are to study the collisions between two protons in the hunt for new elementary particles. Some pieces of the puzzle are missing and the researchers look for among other things the so called Higgs-particles that give all particles mass.

All matter is build up of atoms. Although ‘atom’ is the Greek word for ‘non dividable’ the research of the last hundred years however show that atoms are indeed ‘dividable’. They consist of smaller elements – protons and neutrons that again consist of even smaller elementary particles, and it is these minute and non dividable building bricks that researchers in the field of particle physics are hunting for.

The physical Standard Model describes the elementary particles, the quarks, gluons, leptons, neutrinos, but there is still one very important piece of the puzzle missing; it is the particle that gives all the other particles mass. That particle is called the Higgs-particle and up till now it has never been observed in any experiment. One of the biggest tasks for ATLAS is to look for the Higgs-particle and decide if it really exists or not.

The ATLAS experiment takes place in CERN, the European research centre near Geneva in Switzerland, where a 27 km long tunnel runs in a ring 100 meter underground across the French and Swiss border. Here particles are accelerated to incredibly high speeds in the atomic accelerator, The Large Hadron Collider (LHC) before they collide. At the gigantic collisions particles are created with energies that correspond to the energy of the universe immediately after the Big Bang. In these ‘mini-Big Bangs’ the matter is broken down into minute building bricks, and by using huge and advanced detectors the particle physicists can now study what the particles look like.