Understanding Indirect vs Direct CP Violation: Explained and Compared

[ChrisVer]

Can someone explain or give any ref. where I can find the difference between Indirect and Direct CP violations?

 

[dukwon]

Indirect CP violation is asymmetry in neutral meson mixing. It is "indirect" because the processes $P^0\rightarrow\overline{P}^0$ and $\overline{P}^0\rightarrow P^0$ are both CP-conjugate and T-conjugate, so CP-violation is only implied, and the asymmetry could be due to T-violation

Direct CP violation is asymmetry between CP-conjugate decays, i.e. $\Gamma(P^0\rightarrow f)\neq\Gamma(\overline{P}^0\rightarrow \overline{f})$. Clearly these decays are not T-conjugate, so this is a direct measurement of CP-violation.