Theory of CP violation in B decays

TL;DR

This paper reviews recent theoretical advances in understanding CP violation in B-meson decays, emphasizing methods to control uncertainties, recent puzzles, and progress in describing complex decay processes.

Contribution

It introduces new strategies using flavor symmetries to reduce theoretical uncertainties and discusses recent progress in modeling three-body B decays within QCD factorization.

Findings

Control of theory uncertainties via flavor symmetries.

Identification of a puzzle in the B→πK system.

Progress in describing three-body B decays.

Abstract

The study of CP violation in $B$-meson decays has already reached a high level of precision, which will be pushed even higher in the future era of Belle-II and the LHCb upgrade. %Important probes of CP violation are the $B_d^0$ and $B_s^0$ mixing phases and the CKM angle $\gamma$. Here, the theoretical challenge is to control the uncertainties from strong interactions to distinguish between the Standard Model and possible New Physics effects. In this talk, I will present a selected overview of recent theoretical developments in this field. This includes, in particular, the semileptonic asymmetry $a_{\text{sl}}^s$ and extractions of the CKM angle $\gamma$ and the $B_d^0$ and $B_s^0$ mixing phases. I focus on recently proposed strategies in which the theory uncertainties can be controlled through data using flavour symmetries of the strong interaction. A newly found puzzle in the $B \to \pi K$ system is highlighted and a theoretically clean way to determine the underlying electroweak penguin parameters is discussed. Finally, the recent progress to describe three-body $B$ decays in QCD factorization is discussed.