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

TL;DR

This paper analyzes recent Belle II CP asymmetry data in the $B^0_d o ext{pi}^0 K_S$ decay to shed light on the longstanding $B o ext{pi} K$ puzzle and explore potential new sources of CP violation.

Contribution

It provides an updated analysis of the $B o ext{pi} K$ system incorporating new experimental data to gain fresh insights into CP violation and the puzzle.

Findings

New Belle II data refines CP asymmetry measurements.

Updated analysis offers fresh perspective on the $B o ext{pi} K$ puzzle.

Potential to reveal new CP violation sources in future studies.

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.