Extraction of the CKM phase $\gamma$ from charmless two-body B meson decays

TL;DR

This paper presents a model-independent global fit to experimental charmless B meson decay data to precisely extract the CKM angle gamma, accounting for SU(3) breaking effects.

Contribution

It introduces a comprehensive, least model-dependent method to determine gamma by fitting all relevant decay modes and hadronic parameters simultaneously, including SU(3) breaking effects.

Findings

Fitted gamma value: (69.8 ± 2.1 ± 0.9) degrees.

Results are consistent with the world average.

Improved precision over previous measurements.

Abstract

Utilizing all the experimental measured charmless $B \to PP$, $PV$ decay modes, where $P(V)$ denotes a light pseudoscalar (vector) meson, we extract the CKM angle $\gamma$ by global fit. All the unknown hadronic parameters are fitted with $\gamma$ together from experimental data, so as to make the approach least model dependent. The different contributions for various decay modes are classified by topological weak Feynman diagram amplitudes, which are to be determined by the global fit. To improve the precision of this approach, we consider flavor SU(3) breaking effects of topological diagram amplitudes among different decay modes by including the form factors and decay constants. The fitted result for CKM angle $\gamma$ is $(69.8 \pm 2.1 \pm 0.9) ^{\degree}$. It is consistent with the current world average with a better precision.