Less Minimal Flavour Violation

Understand

We consider the approximate U(2)^3 flavour symmetry exhibited by the quark sector of the Standard Model and all its possible breaking terms appearing in the quark Yukawa couplings.

• Taking an Effective Field Theory point of view, we determine the current bounds on these parameters, assumed to control the breaking of flavour in a generic extension of the Standard Model at a reference scale Lambda.
• In particular, a significant bound from epsilon'/epsilon is derived, which is relevant to Minimal Flavour Violation as well.
• In the up-quark sector, the recently observed CP violation in D -> pi+ pi-, K+ K- decays might be accounted for in this generic framework, consistently with any other constraint.