opportunities await particle physics, with new instruments and
experiments poised to explore the frontiers of high energy, infinitesimal distances, and
exquisite rarity. We look forward to the Large Hadron Collider at CERN to explore the
1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of
electroweak symmetry breaking) and many initiatives to develop our understanding of the
problem of identity: what makes an electron an electron and a top quark a top quark.
Here I have in mind the work of the B factories and the hadron colliders on CP violation
and the weak interactions of the b quark; the wonderfully sensitive experiments around
the world on CP violation and rare decays of kaons; the prospect of definitive accelerator
experiments on neutrino oscillations and the nature of the neutrinos; and a host of new
experiments on the sensitivity frontier. We might even learn to read experiment for clues
about the dimensionality of spacetime.
If we are inventive enough, we may be able to follow this rich menu with the physics
opportunities offered by a linear electron-positron collider and by new-technology
neutrino beams based on muon storage rings. I expect a remarkable flowering of
experimental particle physics, and of theoretical physics that engages with experiment.
Experiments that use natural sources also hold great promise. We suspect that the
detection of proton decay is only a few orders of magnitude away in sensitivity.
searches and astronomical observations should help to tell us what kinds of matter
and energy make up the universe. The areas already under development include gravity
wave detectors, neutrino telescopes, cosmic microwave background measurements,
cosmic-ray observatories, gamma-ray astronomy, and large-scale optical surveys. Indeed,
the whole complex of experiments and observations and interpretations that we call
astro/cosmo/particle physics should enjoy a golden age.
Our theories of the fundamental particles and the interactions among them are in a
very provocative state. The standard model summarizes a simple and coherent
understanding of an unprecedented range of natural phenomena, but our new
understanding raises captivating new questions. In search of answers, we
have made far-reaching speculations about the universe that may lead to revolutionary changes in our
perception of the physical world, and our place in it. Truly, we are entering a remarkable
age of exploration and new physics!