CP Violation in Fourth Generation Quark Decays

We show that, if a fourth generation is discovered at the Tevatron or LHC, one could study CP violation in b' \to s decays. Asymmetries could reach 30% for b'\to sZ for m_{b'} \lesssim 350 GeV, while it could be greater than 50% for b'\to s\gamma and extend to higher m_{b'}. Branching ratios are 10^{-3}--10^{-5}, and CPV measurement requires tagging. Once measured, however, the CPV phase can be extracted with little theoretical uncertainty.