Lessons from the $B^{0,+}\to K^{*0,+}\mu^+\mu^-$ angular analyses

TL;DR

This paper analyzes $B o K^* o ext{muons}$ decays within the Standard Model and beyond, highlighting the importance of hadronic effects and identifying a potential new physics signal with high significance.

Contribution

It provides a comprehensive analysis of $B o K^* ext{muons}$ decays, incorporating recent data, hadronic contributions, and a fit within the Standard Model Effective Theory, revealing a significant new physics hint.

Findings

Hadronic contributions are crucial to explain recent measurements.

A fully left-handed operator scenario shows a nearly 6 sigma significance.

The analysis emphasizes the need for further investigation into new physics signals.

Abstract

We perform an analysis within the Standard Model of $B^{0,+} \to K^{*0,+} \mu^+ \mu^-$ decays in light of the recent measurements from the LHCb experiment, showing that new data strengthen the need for sizable hadronic contributions and correlations among them. We then extend our analysis to New Physics via the Standard Model Effective Theory, and carry out a state-of-the-art fit of available $b \to s \ell^+ \ell^-$ data, including possible hadronic contributions. We find the case of a fully left-handed operator standing out as the simplest scenario with a significance of almost $6\sigma$.