On the new LHCb angular analysis of $B \to K^* \mu^+ \mu^-$: Hadronic effects or New Physics?

TL;DR

The paper evaluates whether the anomalies in LHCb's $B o K^* o ext{muons}$ decay are due to new physics or underestimated hadronic effects, using new data and statistical tests to clarify their origin.

Contribution

It introduces two statistical tests to distinguish between hadronic effects and New Physics explanations for the observed anomalies in $B o K^* o ext{muons}$ decay.

Findings

The tests favor either New Physics or hadronic effects as explanations.

Updated global fits incorporate new LHCb data.

The usefulness of the tests is analyzed in future scenarios.

Abstract

The new angular analysis of the decay $B \to K^* \ell^+ \ell^-$ recently presented by the LHCb Collaboration still indicates some tensions with the Standard Model predictions. There are several ongoing analyses to solve the problem of separating hadronic and New Physics effects in this decay, but the significance of the observed tensions in the angular observables in $B \to K^* \mu^+\mu^-$ is still dependent on a theory guesstimate of the hadronic contributions to these decays. Using the new data from LHCb we offer two tests which make a statistical comparison to determine whether the most favoured explanation of the anomalies is New Physics or underestimated hadronic effects. We then analyse the usefulness of these tests in two future scenarios. Finally, we update our global fits to all available $b \to s $ data and discuss the impact of the new LHCb measurements.