Wednesday, February 16th, 2011
2:30pm - 4:00pm, in McCormack 2-116

Amir Aczel

University of New Hampshire

Looking at the Large Hadron Collider

Abstract: I will discuss the largest-scale experiment in history, currently taking place inside the Large Hadron Collider at CERN, in a 16.5-mile circular tunnel 300 feet underground in the border region of Switzerland and France outside Geneva, in which protons are collided at speeds within epsilon of the speed of light (well, the speed is better than 99.9999%C and going up to 99.9999991%C) in an effort to uncover the details of a symmetry-breaking mechanism, known by physicists as the Higgs mechanism and associated with the hypothesized existence of a boson popularly known as the ``God particle.'' This theoretically-derived mechanism, which was used by Steven Weinberg and Abdus Salam in their Nobel Prize winning work four decades ago, posits a spontaneous breakdown of the Lie group SU(2)xU(1) associated with a unified electroweak force into a diagonally-embedded U(1) group, which is not the original U(1) group of electromagnetism. The symmetry-breaking mechanism is believed to have enabled the emergence of mass in the early universe. The much hoped for discovery at CERN of evidence of the Higgs boson will provide experimental support for the theorized symmetry-breaking process and hence for the entire Standard Model of particle physics, in which the larger Lie group SU(3)xSU(2)xU(1) is used to model three of the four forces of nature--the strong force (modeled by SU(3)) and the electromagnetic and weak forces. The fourth force, gravity, still awaits future unification--perhaps through string theory--whose experimental verification is believed to be outside the energy range of the LHC (its maximum is 14 TeV).