In this chapter we will discuss flavor physics of leptons, in particular charged lepton decays mediated by flavor changing neutral currents. While very strongly suppressed within the SM, lepton flavor violation (LFV)can be by many orders of magnitude larger in NP models. Therefore finding such transitions would be a clear signal of NP.The nice feature of most of these decays is the absence of QCD corrections, making the theoretical analysis much simpler than was the case of meson decays. Another important topic are electric dipole moments (EDMs) of various atoms, molecules, nuclei, and nucleons that all are very strongly suppressed in the SM. They test CP violation without flavor violation. Similar to LFV, a measurement of any nonvanishing EDM would be a clear signal of NP at work. But in contrast to LFV there are large nonperturbative uncertainties in this case. In this part we will also discuss anomalous magnetic moments of charged leptons. We will present a compendium of formulas for many observables. These formulasare quite general so that one canuse them for various models. We will illustrate them on a few examples.

We will next move to discuss the Standard Model (SM) of electroweak and strong interactions. We will present the basic SM Lagrangian, andwe will discuss various properties of this simplest theory, but we will not do any phenomenology at this stage. There are many excellent books on the dynamics of the SM, and we will in most cases skip derivations of well-known formulae to save space and in particular energy for the later steps that are not covered in detail in textbooks. The most important result of this step will be collection of the Feynman rules for those interactions present in the SM that we will need for explicit calculations as we proceed. For readers' convenience we will collect these rules in an Appendix.