中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

The flavor invariants, which are invariant under the unitary transformation in the flavor space, turn out to be a powerful tool in studying the CP violation in a model-independent way. In this talk, I will discuss the application of the flavor invariants in constructing the sufficient and necessary conditions of CP conservation in the leptonic sector with Majorana neutrinos. Furthermore, the systematic construction of all the basic invariants using the method of Hilbert series will be briefly introduced.