Thursday, October 27, 2005, 16:00
WHGA Auditorium
G. Colangelo, Bern University
Abstract:
The gyromagnetic ratio of leptons has been measured with
increasing accuracy during the last 60 years, and it is known today to
0.5 parts per million for the muon and to 3 parts per billion for the
electron. This breathtaking precision is matched by the theory and
represents a thorough test of our current understanding of particle
physics. While for the electron quantum electrodynamics is all is
needed to calculate $a_e$ to the necessary accuracy, for the muon the
full structure of the standard model comes into play. The latest
experimental results for the muon have shown some hints of a possible
disagreement with the standard model. After a brief look back at some
history of this fascinating research field, I will discuss what is being
done today to answer the urgent question: has new physics already been
discovered in the muon (g-2)?