ATLAS - High Energy Physics

The HEP group at the Niels Bohr Institute work with accelerator-based experiments, presently the ATLAS experiment at CERN, the world's leading laboratory for particle physics research. 

Sizes of atmoms, nuclei and quarksHigh Energy Physics, also known as Particle Physics, is the field of physics that investigates the nature of the Universe by studying its fundamental constituents, the particles. This is done by studying the behavior of matter at the extreme energies reached in particle accelerators or observed in ultra-high-energy cosmic rays.

The present knowledge is contained in the Standard Model, which describes how all matter is made up of leptons (such as electrons and neutrinos) and quarks. It also describes how the basic electromagnetic, strong and weak forces act on the leptons and quarks in order to build the world around us.

Particles from the standard modelThe Standard Model

One of the biggest challenges in particle physics is to find the missing piece of the Standard Model giving rise to the medley of particle masses we observe. The favored candidate for this is the Higgs mechanism, which requires the existence of a new massive particle: The Higgs boson.

But even though the Standard Model has been verified with impressive precision, nobody believes it is the whole story. Many extensions and new models exists today, such as super symmetry or extra dimensions, and nobody really knows what lies at the high-energy frontier of particle physics. So the coming years will be very exciting!

ATLAS detector illustrationATLAS: The ATLAS experiment seeks to uncover physics beyond the Standard Model. It is located at the Large Hadron Collider (LHC) at CERN. ATLAS is the largest particle physics detector ever built and also represents one of the biggest international collaborational efforts. More than 2000 physicists from 34 countries and 150 institutions are working together on ATLAS. The Danish contribution is based at the Niels Bohr Institute and directed into many areas of the experiment.

NorduGrid: The group is also involved in the development of the infrastructure necessary to cope with the storage and analysis of the enormous data-flow from the ATLAS experiment. This task is solved with innovative GRID technology, and the Niels Bohr Institute contributes to Nordugrid - the very successful Nordic implementation of the GRID.

DUKS: (Dansk Uddannelsesorienteret Kosmisk Stråle projekt) is a pilot project to establish an array of particle detectors on high-schools.

Previous experiments:

HERA-B: The HERA-B experiment, located at DESY in Hamburg, took data until spring 2003. The data is valuable for understanding the physics of b and c quarks and the strong interaction in general.

ALEPH: The ALEPH experiment ran in the years 1989-2000 at the LEP collider at CERN. ALEPH has played an important role in the establishment of the Standard Model as it is today. Among other measurements, it has shown that there exists precisely three generations of quarks and leptons.