# Penguin pollution in $\beta$ and $\beta_s$

## TL;DR

This paper analyzes penguin contributions to CP asymmetries in B meson decays, using QCD factorization and SU(3) symmetry, including new results for $b o car{c}d$ modes, to improve the precision of CP phase measurements.

## Contribution

It provides a detailed calculation of penguin pollution in B decays using soft-collinear factorization and compares it with SU(3) symmetry methods, including novel results for specific decay modes.

## Key findings

- Penguin contributions can be comparable to current experimental errors.
- QCD factorization offers a systematic approach to estimate penguin pollution.
- Results for $b o car{c}d$ modes are presented for the first time.

## Abstract

The mixing-induced CP asymmetries in $B_d \to J/\psi K_S$ and $B_s \to J/\psi \phi$ are essential to detect or constrain new physics in the $B_d\! - \overline{\!B}{}_d$ and $B_s\! - \overline{\!B}{}_s$ mixing amplitudes, respectively. To this end one must control the penguin contributions to the decay amplitudes, which affect the extraction of fundamental CP phases from the measured CP asymmetries. Although the "penguin pollution" is doubly Cabibbo-suppressed, it could compete in size with current experimental errors. In this talk I present a calculation of the penguin contributions treating QCD effects with soft-collinear factorisation and compare method and results with the alternative approach employing flavour-SU(3) symmetry. As a novel feature, I present results for the penguin pollution in $b\to c\overline c d$ modes.