A summer student position is available in the experimental particle physics group of the Physics Department of McGill University. The group consists of six faculty members actively participating in three international collaborations on fundamental research.

The HERA accelerator is located in Hamburg, Germany. 27.5 GeV electrons (or positrons) are colliding with 820 GeV protons. If one defines the quantity Q² as a measure of the momentum transferred between the two particles at collision time, and if one uses the fact that the electron can be considered point-like, the de Broglie wavelength associated to the electron makes it an ideal probe of the proton internal structure. Indeed, as in the case of X-rays with the structure of crystals, the higher the Q² value (hence the smaller the wavelength), the smaller the investigated scale becomes, down to 10^-18 meters!

In this context, the proton content in terms of quarks and gluons, the more fundamental constituents of matter, can be investigated in detail. One already knows that protons foremost contain three valence quarks made from the lightest quarks («up» and «down»). The next intermediate quarks, originating from the proton sea of quarks, are the «strange» and the «charm» quark. The heaviest quarks («top» and «bottom») are so massive that their production is much less probable than the others' by several orders of magnitude.

The goal of this work is the determination of the strange quark production rates through the observation of kaons and lambda particles generated in the collisions. The particles' decay modes are known. Since one measures their decay products in the ZEUS detector, one is therefore able to compare the particle production rates to those predicted by several theoretical models. This analysis will contribute to a further increase in our understanding of the proton structure.

The works consists mainly in experimental data handling and analysis. The computer workstations are UNIX machines, and the programming language is FORTRAN. All basic programs already exists, but those specific to this analysis still must be written and developed. The data themselves from the ZEUS experiment are already available and most of them already on disk.

The summer work in the physics department will be done under the direct supervision of a faculty member. Other colleagues, technicians and students moreover constitute the daily working environment.

                          Prof. François Corriveau

                          McGill University
                          Department of Physics
                          3600, University Street
                          Montréal, Québec
                          Canada, H3A 2T8

                    Tel:  (514)-398-6515
                    Fax:  (514)-398-3733
                 E-mail:  corriveau à physics.mcgill.ca
               Web Page:  http://www.physics.mcgill.ca/~corriveau