CP Violation at CFTP and the EPS particle physics Prize 2007

One of the main topics of research of CFTP is the origin of CP violation, which is also intimately related to the Creation of Matter in the Universe, as well as to the understanding of fermion masses and mixing, the so-called Mass Problem, one of the most profound questions in Fundamental Physics. It is therefore with great excitement that we see the prestigious European Physical Society High Energy and Particle Physics Prize to be awarded for 2007 to Makoto Kobayashi and Toshihide Maskawa (See included below the Press release from KEK, on the 6th of July 2007).

The recent measurement of gamma by BaBar and Belle provided irrefutable evidence that the CKM (Cabibbo Kobayashi and Maskawa) matrix is indeed complex thus confirming the pioneering proposal of Kobayashi and Maskawa in 1973. This important conclusion was also stated in works involving collaborations of CFTP members, e.g. in New physics and evidence for a complex CKM, Nucl. Phys. B 725 (2005) 155 by F.J. Botella, G.C. Branco, M. Nebot and M.N. Rebelo or recently in Yukawa Textures, New Physics and Nondecoupling to be published in Phys. Rev. D, by G.C. Branco, M.N. Rebelo and J.I. Silva-Marcos.

Another important aspect of the origin of CP violation is the question of whether CP is a good symmetry of the Lagrangian, only broken by the vacuum. In the context of Supersymmetric Theories it is a great challenge to construct models where CP is spontaneously broken and yet the CKM matrix is complex. One of the rare examples of such a model was constructed by CFTP members: Spontaneous CP Violation in a SUSY Model with a complex CKM by G.C. Branco, D.Emmanuel-Costa, J.C.Romao, published in Phys. Lett. B 639 (2006) 661.

It is also known that the strength of CP violation in the Standard Model is not sufficient to generate the Baryon Asymmetry of the Universe (BAU). Almost all extensions of the Standard Model including Supersymmetry have new sources of CP violation. The members of CFTP have been actively investigating models with possible additional sources for CP violation and also the generation of (BAU) through leptogenesis. These are some of the present hottest topics in Particle Physics. Click here for an extensive list of papers of CFTP written on CP violation.

One of the best general references on CP violation is the book written by three CFTP members, published in the Oxford International Series of Monographs on Physics, the same series where appeared the famous Dirac Book on Quantum Mechanics: CP Violation, Gustavo C. Branco, Luis Lavoura, Joao P. Silva, International Series of Monographs on Physics, No. 103 Oxford University Press. Oxford, UK: Clarendon (1999) 511 p. (The three CFTP members who authored this Book received The Gulbenkian Science Prize for this work).

Press release from the KEK:

The prestigious European Physical Society High Energy and Particle Physics Prize was awarded for 2007 to Makoto Kobayashi and Toshihide Maskawa for "the proposal of a successful mechanism for CP violation in the Standard Model, predicting the existence of a third family of quarks". Kobayashi is a professor emeritus of KEK and the former Director of the Institute of Particle and Nuclear Studies, the High Energy Accelerator Research Organization (KEK), Japan.

Kobayashi, together with Maskawa, proposed six types of quarks and their mixing matrix for the weak interaction in 1973. Later in 1995, the sixth quark was discovered,and in 2001, KEK and SLAC confirmed the CP violation using B mesons at their B-factory experiments Belle and BaBar.