University of Pennsylvania
Department of Physics and Astronomy
Primakoff Colloquium

Abstract

In the last 30 years, there has been a tremendous advance in our understanding of the elementary particles and their interactions. We now have a mathematically consistent theory of the strong, electromagnetic, and weak interactions - the standard model - which is almost certainly the correct description of Nature down to a distance scale 1/1000th the size of the atomic nucleus. However, nobody believes that the standard model is the ultimate theory - it is too complicated and arbitrary.

There are many ideas for improvements, the most promising being superstrings. The string energy scale is close to the Planck scale, some sixteen orders of magnitude higher than the reach of foreseeable experiments. Nevertheless, careful examination of a variety of string models hints at observable signatures, such as new particles and interactions, and possibly supersymmetry. Implications for accelerator physics, dark matter, the origin of the baryon asymmetry in the universe, and the masses of neutrinos will be discussed.