Study of proton-proton interactions in the CMS-experiment at the Large Hadron Collider in CERN.

The subject of this project is the analysis of data that will be collected with the CMS detector at the LHC collider in CERN. The interest of physicists working at the universities of Antwerp and Brussels is broad and includes mainstream subjects at the LHC such as supersymmetry and the search for the Higgs boson. In this proposal however, we focus on two particular subjects, namely top quark physics and diffraction and "forward" physics at the LHC. Two of the applicants (Pierre Van Mechelen and Albert De Roeck) are active in the H1 experiment at the HERA collider and have acquired expertise in diffraction and the structure of the proton at low fractional momenta of the struck quark ("low Bjorken-X"). Albert De Roeck is also active in the CMS experiment. Two other applicants (Jorgen D'Hondt and Catherine De Clercq) have been active in the DELPHI experiment at the LEP collider. Jorgen D'Hondt is however already active in the CMS collaboration for some time and is responsible for the construction of tracking detector modules and developed a method for accurate reconstruction of the top quark mass at the LHC. The applicants wish to develop research activities within the CMS collaboration. Contributions to a Belgian TIER-2 GRID computing centre and to the construction of the CASTOR detector, both important parts of the project, are essential for the participation of Flemish physicists in CMS.