CP violation in charm

Charm transitions play a unique dual role in the modern investigations of flavor physics. They provide valuable supporting measurements for studies of CPviolation in B-decays, such as formfactors and decays constants, as well as outstanding opportunities for indirect searches for physics beyond the Standard Model (SM). It must be noted that in many dynamical models of new physics the effects of new particles observed in s, c, and b transitions are correlated. Therefore, such combined studies could yield the most stringent constraints on parameters of those models. For example, loop-dominated processes such as D0−D0 mixing or flavor-changing neutral current (FCNC) decays are influenced by the dynamical effects of down-type particles, whereas up-type particles are responsible for FCNC in the beauty and strange systems. Finally, from the practical point of view, charm physics experiments provide outstanding opportunities for studies of New Physics because of the availability of large statistical samples of data. CP-violation can be introduced in Quantum Field Theory in a variety of ways [1]. One way, CP-violation can be introduced explicitly through dimension-4 operators (the so-called “hard” CP-breaking). This is how CP-invariance is broken in the Standard Model via quark Yukawa interactions,