Flavour Dynamics: CP Violation and Rare Decays

Abstract

These lectures give an up to date description of CP violation and rare decays of K and B mesons and consist of ten chapters: i) Grand view of the field including CKM matrix and the unitarity triangle, ii) General aspects of the theoretical framework based on effective weak Hamiltonians, the operator product expansion and the renormalization group, iii) Particle-antiparticle mixing and various types of CP violation, iv) Standard analysis of the unitarity triangle, v) The ratio ε ′ /ε, vi) Rare decays K + → π + νν and K L → π 0 νν, vii) Express review of other rare decays, viii) CP violation in B decays, ix) A brief look beyond the Standard Model discussing in particular the models with minimal flavour violation, x) Perspectives for the coming years.Lectures given at the 38th Course of the Erice International School of Subnuclear Physics:

Enhancement ofB(Bd→μ+μ−Bobeth1, Ewerth2, Krüger3 et al. 2002Phys. Rev. D1075800View full textAdd to dashboardCite

“…The common feature of these MFV definitions is that flavour violation and/or flavour-changing neutral current (FCNC) processes are entirely governed by the CKM matrix. On the other hand, they differ, for example, by the following additional assumptions: i) there are no new operators present, in addition to those of the SM [1,8,12,13], ii) FCNC processes are proportional to the same combination of CKM elements as in the SM [14], iii) flavour transitions occur only in charged currents at tree level [15].…”

“…(3.5), and using the ranges for the CKM factors given in Ref. [1], the ratio of decay rates ofB d,s → µ + µ − within the SM is expected to be in the range 0.02 R SM 0.05, (3.8) which is largely due to the imprecisely known CKM elements.…”

“…The contributions due to neutral Higgs boson exchange, on the other hand, are suppressed by a factor of m l m b,q /M 2 W 10 −3 , and therefore are completely negligible. The SM predicts theB s → µ + µ − branching ratio to be [1,2] B (B s → µ + µ − ) = (3.2 ± 1.5) × 10 −9 , (1.1) and the ratio of branching fractions…”

“…Working in the framework of the Minimal Supersymmetric Standard Model (MSSM) with a large ratio of Higgs vacuum expectation values, tan β (ranging from 40 to 60), we show that such a scenario does exist, and study its consequences for theB d,s → µ + µ − branching ratios. 1 To this end, we extend our previous analysis [2] to include the effects of gluino and neutralino contributions, in addition to those coming from diagrams with W ± ,χ ± , charged and neutral Higgs boson exchange. The outline of this paper is as follows.…”

Lepton flavor violation in the Simplest Little Higgs model

“…Thus, it is important not only to investigate the requirements for constructing realistic LH models, but to eventually interpret any possible departure from the SM predictions which may be observed at ongoing or planned high precision flavor experiments like MEG [31,32] at PSI and PRISM/PRIME [33,34] at J-PARC. A general discussion of different scenarios, including the LHT model as well as supersymmetric and extra dimensional models, can be found in [35,36]. The comparison of muon and τ branching fractions, when the latter are known with a better precision, should eventually help to discriminate between specific models [37].…”