Dirac Medallists 1996

Tullio Regge, Politecnico di Torino, Italy

for crucial contributions in theoretical and mathematical physics starting with his seminal investigation of the asymptotic behaviour of potential scattering processes through the analytic continuation of the angular momentum to the complex plane. This technique has found many applications in the study of differential equations while in the physics of the Strong Interactions, the so-called Regge trajectories have helped in the classification of particles and resonances by grouping together entities with different spin. The so-called Regge behaviour was, and still is, an important ingredient in the construction of String theories. In addition, Regge is also known for having introduced the first discretisation of space-time with a simple Einstein dynamics (the so-called Regge Calculus) and for his formulation of supergravity theories in the geometric language of differential forms.

Martinus J.G. Veltman, University of Michigan, Ann Arbor, USA

for his pioneering investigations on the renormalisability of gauge theories and consequently, his analysis of the sensitivity of radiative corrections to both the mass differences in fermion doublets and the Higgs particle mass. These calculations provided the basic prediction in the search for the Top quark mass. Towards this goal, Veltman was one of the first to use the computer in Feynman diagram calculations. His software package for manipulations of algebraic symbols has been a privileged tool for a full generation of physicists.