Woensdag 7 januari 2009
||Gerard 't Hooft (Universiteit Utrecht)
||The CKM Matrix: a Question of Flavor
||11:00 - 12:00
Vanaf kwart voor 11 is er koffie en thee voor de zaal.
The latest Nobel Prizes were for three elementary particle
physicists of Japanese origin, Y. Nambu, M. Kobayashi and T. Maskawa.
The first stood at the basis of the development of the
Englert-Brout-Higgs theory for spontaneous symmetry breakdown in
particle physics. The last two made an essential step by casting the
coupling between the Higgs field and the quarks in the form of a matrix.
This matrix not only describes the masses and the weak interaction
parameters of the quarks, thus defining their "flavor" properties, but
also allows for one effect that is not symmetric under CP, the
combination of a parity inversion and the replacement
particle-antiparticle. This gave an elegant explanation of CP violation
in the weak interactions, provided that the matrix was at least three
dimensional. It turned out to be the first hint for the existence of a
third generation of quarks and leptons. Careful analysis of the relation
between this matrix and experimental data is used to investigate whether
the Standard Model of the Subatomic Particles, as it is known today,
needs to be extended.