Utilising $B \to πK$ Decays at the High-Precision Frontier

Abstract

For about twenty years, $B\toπK$ decays are in the focus of $B$-decay studies. We show that a correlation between the CP asymmetries of $B^0_d\toπ^0K_{\rm S}$ reveals a tension with the Standard Model. Should it be due to New Physics, a modified electroweak penguin sector provides particularly interesting possibilities. We present a new method to determine the electroweak penguin parameters, which uses an isospin relation and requires only minimal $SU(3)$ input. We apply it to the current data for $B\toπK$ decays and discuss the prospects for utilizing CP violation in $B^0_d\toπ^0K_{\rm S}$. The strategy has the exciting potential to establish New Physics in the electroweak penguin sector in the high-precision era of $B$-physics.

6 pages, 2 figures, talk given at Rencontres de Moriond 2018, QCD and High Energy Interactions, La Thuile, Italy, 17-24 March 2018, to appear in the Proceedings; v2: references added