Michael Luke


Theoretical particle physics: quantum chromodynamics, weak interactions, effective field theories, heavy quark physics.

Telephone:  416-978-2985
Fax: 416-978-2537
E-mail: luke @ physics.utoronto.ca
Web links: Theory Group Page
High Energy Physics/Theory/String Seminar


Brief CV

B.Sc., Toronto (1987); Ph.D., Harvard (1991), Postdoctoral, University of California, San Diego (1991-1993); Assistant Professor, University of Toronto (1993-1998), Visiting Assistant Professor, University of California, San Diego (spring, 1994); Sloan Fellow (1996-1998), Visiting Associate, Caltech (fall, 1998); Associate Professor, University of Toronto (1998-2002); Special Scientist, Lawrence Berkeley Laboratories (spring, 2001); Professor, University of Toronto (2002- ); CAP Herzberg Medal (2003); Interim Chair, Department of Physics (2004-2006); Chair, Department of Physics (2006-2013); Fellow, American Physical Society (2009).

Research Interests

Most of my recent research has been concerned with the weak interactions of quarks, and theoretical problem of disentangling the weak interactions responsible for quark decay from the effects of the strong force (quantum chromodynamics, or QCD) which binds quarks and gluons into the observed hadrons.

Of particular current interest, both theoretically and experimentally, are the decays of hadrons containing bottom (b) quarks. The decays of the b quark yield a great deal of information on the details of the weak interaction in the third, least understood, generation of matter. Because of its large mass and strong coupling to the top quark the decays of the b quark are also sensitive to the effects of new, as yet undiscovered particles. However, since b quarks only occur inside hadrons and are never observed freely, a great deal of theoretical effort is required to disentangle the strong and weak interactions to allow us to interpret experimental results.

A strikingly successful approach which has been developed over the past few years is based on perturbing about the infinite mass limit of a heavy quark and has led to precise, model-independent predictions. These techniques are now allowing us to extract fundamental parameters such as quark masses and mixing angles from experiment. Applying these techniques to rare decay modes of the b quark is allowing us to test the nature of the weak interactions to high precision, probing physics at energies of the order of several hundred GeV (corresponding to distances of about one thousandth of the radius of the proton).

Another application of these techniques is the study of heavy quark-antiquark bound states, such as the J/psi and the upsilon (charm-anticharm and bottom-antibottom bound states, respectively). These states are considered the ``hydrogen atoms'' of QCD, since they are bound at such short distances that the strong force behaves approximately like electromagnetism. The degree to which this picture is valid, the corrections to it, and the experimental implications are all subjects of recent work in our group. Although the top quark does not live long enough to form bound states, we are also using the same approach to study in detail top-antitop production near threshold.

In the opposite limit, the properties of hadrons containing light (up, down and strange) quarks may also be studied, in this case by perturbing about the massless limit. The resulting theoretical tools also turn out to be very useful in studying the effects of hypothetical strongly-interacting particles which may be responsible for the observed masses of the weak gauge bosons W± and Z0.

Here are a couple of one-page summaries of what we do (click to read):

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Selected Publications

A complete and up-to-date list of my publications is available from the SPIRES database at SLAC.

Here is a review article on the mass of the b quark I wrote in collaboration with Aida El-Khadra (published in Ann. Rev. Nucl. Part. Sci. 52, 201 (2002) ).

My 2002 TASI lectures, "Bottom quark physics and the heavy quark expansion."

Selected Talks


Seminars/Conference talks


Current Graduate Students:

  • William Cheung (Ph.D. student)
  • Simon Freedman (Ph.D. student)
  • Saba Zuberi (Ph.D. student)

Former Graduate Students:


Former Postdocs:

This site is maintained by Michael Luke. Last updated: November 13, 2009.