Robert S. Orr High Energy Particle Physics (Experimental)


Robert S. Orr


B.Sc. (1968), Ph.D. (1972) Imperial College, London University;

Spokesperson of ATLAS Canada; CERN Scientific Associate; Fellow of the American Physical Society

Experimental Studies of the Standard Model of Particle Physics, in particular the origin of electroweak symmetry breaking; participation in the ATLAS and CDF experimental programs; development of new detector technologies for particle physics.

Telephone: (416)-978-6029

Fax: (416)-978-8221



Web-site address:






Research Interests

My research is part of a wide collaborative experimental effort to understand what lies beyond our present ideas on the most fundamental structure of matter. In the twenty years from 1975, the interplay between experiment (see for example my first two "Selected Publications") and theory, has led to a synthesis known as the standard model; it encompasses all presently known phenomena in particle physics. It also points to the existence of new phenomena which should be accessible to the generation of experiments now under construction.

My own work is part of the ATLAS collaboration. ATLAS is a large general purpose detector which will operate at the CERN Large Hadron Collider, starting in 2005. At Toronto I work on the construction of an innovative particle detector (see photograph) which will be instrumental in the search for at least two of the new phenomena mentioned above; Supersymmetry, and the origin of electroweak symmetry breaking ( the mechanism which generates the masses of particles). This detector is the outcome of a long term at programme at Toronto aimed at developing very radiation hard particle detectors. Only such detectors can function close to the high intensity LHC beams.

In addition to my work on ATLAS, I am part of the CDF collaboration at Fermilab. In the upcoming CDF runs, we hope to get a first glimpse of the new phenomena expected at the LHC.

Selected Publications

"Observation of New Particle Production by High Energy Neutrinos and Anti-Neutrinos", A. Benvenuti et al., Phys. Rev. Lett. 34, 7, 419 (1975).

"Measurement of the Cross Section of Anti-Neutrino Scattering on Electrons", M. Jonket et al., Phys. Lett. 105B, 242 (1981).

"Observation of Mixing. ARGUS Collaboration., H. Albrecht et al., Phys. Lett. 129B, (245) (1987).

"Study of Charged-Current ep Interactions at > 200 GeV" with the ZEUS Detector at HERA, ZEUS Collaboration, M.Derrick et al., Zeitschrift f. Physik C72 (1996) 47-64.

"Comparison of ZEUS Data with Standard Model Predictions for Scattering at High x and ", ZEUS Collaboration, J. Breitweg et al., Zeitschrift f. Physik C74 (1997) 207-220.

"High Energy Beam Tests of the ATLAS Tungsten Forward Calorimeter.", J.K. Mayer et al., Proceedings of "5th International Conference on Advanced Technology and Particle Physics", Como, Italy, October 5-9, 1998