Anomalies in Hadronic $B$ Decays

Abstract

The decays $B\to PP$, where the pseudoscalar $P$ is a $\pi$ or $K$, have been studied under the assumption of flavour SU(3) symmetry [SU(3)${}_F$]. The global fit shows a 3.6$\sigma$ discrepancy with the Standard Model (SM). Separate fits for $\Delta S=0$ and $\Delta S=1$ decays find parameter sets that differ by a factor of 10, suggesting 1000% SU(3)${}_F$ breaking, significantly larger than the $\sim$ 30% breaking expected in the SM. This study has been extended to include final states with $\eta$ and ${\eta }^{\prime }$ mesons. The resulting global fit, once again under the assumption of SU(3)${}_F$ symmetry, is worse, with a 4.1$\sigma$ deviation from the SM. When theoretical constraints $|\tilde{C}/\tilde{T}|=0.2$ or $\tilde{A}=0$ are imposed, the fits worsen, with the discrepancy approaching 5$\sigma$. These results hint at new-physics contributions to these decays.

7 pages, contribution to the Proceedings of the XVI International Conference on Beauty, Charm, Hyperons in Hadronic Interactions (BEACH 2026), 7-12 June 2026, Firenze, Italy