SPIN

Experimental Subatomic Physics


Rob Pywell, Ru Igarashi, Norm Kolb (on leave), Jack Bergstrom (Emeritus)

Very high-energy photons, known as gamma rays, are used to probe the properties of nucleons (neutrons and protons) and the nucleus. In the past, our group performed experiments at the former Saskatchewan Accelerator Laboratory (SAL), now the Canadian Light Source (CLS), and recently at a facility in Mainz, Germany. Future experiments will be performed at a new facility known as the High Intensity Gamma-Ray Source (HIGS) at Duke University in North Carolina, USA ( http://higs.tunl.duke.edu). This facility generates gamma rays with a completely new technique that will make it possible to extend the ground-breaking experiments performed at SAL and Mainz into new areas, allowing new physics to be measured with unprecedented accuracy. A substantial  grant from the Natural Science and Engineering Research Council was awarded to carry out this research.

We have some exciting experimental programs just beginning. We invite students interested in an M.Sc. or Ph.D. degree to work with us. These programs are an extension of the highly successful ones at the former SAL involving studies of fundamental properties of nucleons and light nuclei. These include measurements of near-threshold pion production (which provides stringent tests of Quantum Chromodynamics (QCD) using Chiral Perturbation Theory), measurements of fundamental nucleon properties such as the electric and magnetic polarizabilities, and studies of multi-nucleon dynamics in few-body systems. Our current focus in on a measurement of the double-polarization cross sections (polarized beam and polarized target) for the photodisintegration of the deuteron from threshold (2.2 MeV) up to ~140 MeV. This tests some fundamental assumptions, used in understanding subatomic systems, through what is known as a `sum-rule'.

Our previous students have enjoyed a unique graduate student experience. Working in experimental collaborations that are relatively small, by today's standards, students have been able to get hands-on experience in all areas of experimental physics---beam production, target and detector design and construction, data acquisition electronics (hardware and software), and data analysis techniques (including simulation and modeling software). Very often in large collaborations at larger facilities a student will gain experience in only a few of these areas. We have found that students, upon graduation, have been much sought after and appreciated in the subatomic physics community for the depth of their experience. Students working with us in these new experimental programs will have a very similar educational experience to what past graduate students have enjoyed. For further information, including how to contact us, see our website at http://nucleus.usask.ca