CP violation in meson decays

This is a written version of a series of lectures aimed at graduate students in the field of (theoretical and experimental) high energy physics. The main topics covered are: (i) The flavor sector of the Standard Model and the Kobayashi-Maskawa mechanism of CP violation; (ii) Formalism and theoretical interpretation of CP violation in meson decays; (iii) K decays; (iv) D decays; (v) B decays: b -> c c-bar s, b -> s s-bar s, b -> u u-bar d and b -> c u-bar s, u c-bar s; (vi) CP violation as a probe of new physics and, in particular, of supersymmetry.Comment: 67 pages, 7 figures; Lectures given at the `Third CERN-CLAF School of High Energy Physics', Malargue (Argentina) 3/2005, and at the Les Houches Summer School (Session LXXXIV) on `Particle Physics Beyond the Standard Model,' Les Houches (France) 8/200

The scale of supersymmetry breaking as a free parameter

While supersymmetric extensions of the Standard Model can be fully described in terms of explicitly broken global supersymmetry, this description is only effective. Once related to spontaneous breaking in a more fundamental theory, the effective parameters translate to functions of two distinct scales, the scale of spontaneous supersymmetry breaking and the scale of its mediation to the standard-model fields. The scale dependence will be written explicitly and the full spectrum of supersymmetry breaking operators which emerges will be explored. It will be shown that, contrary to common lore, scale-dependent operators can play an important role in determining the phenomenology. For example, theories with low-energy supersymmetry breaking, such as gauge mediation, may correspond to a scalar potential which is quite different than in theories with high-energy supersymmetry breaking, such as gravity mediation. As a concrete example, the Higgs mass prediction will be discussed in some detail and its upper bound will be shown to be sensitive to the supersymmetry breaking scale.Comment: 9 pages, 1 figure (included). Requires espcrc2.sty (included). Talk given at the 30 Years of Supersymmetry workshop, Oct. 200

Dynamical mean-field approximation for unitary Fermi gas

Dynamical mean-field approximation with explicit pairing is utilized to study the properties of a two-component Fermi gas at unitarity. The problem is approximated by the lattice Hubbard Hamiltonian, and the continuum limit is realized by diluting the lattice. We have found that at zero temperature the predictions of this theory for the energy and the pairing gap agree remarkably well with the results of full numerical Monte-Carlo simulations. Investigating the evolution of the system with temperature we identify the existence of a second order phase transition associated with a jump in the heat capacity and the collapse of the pairing gap.Comment: 4 pages, 3 figure