Shedding New Light on the ${B \to \pi K}$ Puzzle

Abstract

The $B \to \pi K$ system provides a rich laboratory for testing the Standard Model and studying CP violation. A particularly important channel is $B^0_d\to\pi^0 K_{\rm S}$, the only mode exhibiting both direct and mixing-induced CP violation. Recent Belle II measurements of the CP asymmetries in this decay provide valuable new input. An updated analysis incorporating these new data provides new insight on the long-standing $B \to \pi K$ puzzle. Looking ahead to the high-precision era of flavour physics, the $B \to \pi K$ system can be further exploited to potentially reveal new sources of CP violation.