Constraints on New Physics from $B$ mesons

TL;DR

This paper reviews the current status of New Physics effects in B meson decays, highlighting anomalies, tensions with Standard Model predictions, and the potential of kaon physics to probe high energy scales.

Contribution

It provides an updated overview of flavor anomalies, tensions in B meson mixing, and emphasizes the importance of kaon physics as a probe of high-energy phenomena.

Findings

Anomalies in charged and neutral current B decays related to lepton flavor universality.

Tensions in neutral B meson mixing observables compared to Standard Model predictions.

Kaon physics offers a unique window into very high energy scales.

Abstract

These proceedings review the status of New Physics contributions to flavour violating $B$ decays. The anomalies in charged and neutral current $B$ decays related to lepton flavour universality violation have received a substantial amount of attention over the past years, and we discuss the current status in light of the new data presented earlier this year. We also recall a tension in the neutral $B$ meson mixing observables $\Delta M_d$ and $\Delta M_s$ and in particular their ratio, when compared with their SM predictions obtained using tree-level determinations of the CKM matrix and the recent lattice QCD results for the relevant hadronic matrix elements. Last but not least, we advocate kaon physics as a unique probe of very high energy scales and briefly discuss the current status of $\varepsilon'/\varepsilon$ and $K\to\pi\nu\bar\nu$.