Data-driven analyses and model-independent fits for present $b\to s \ell \ell$ results

TL;DR

This paper critically assesses current $b o s \, \ell\ell$ anomalies using QCD factorisation, analyzing form factors, bin effects, and model-independent fits with new LHCb and CMS data, exploring whether tensions are due to underestimated hadronic effects or new physics.

Contribution

It provides a comprehensive, model-independent analysis of $b o s \, \ell\ell$ anomalies incorporating recent experimental data and evaluates the role of non-factorisable corrections in these tensions.

Findings

Updated global fit with new LHCb and CMS data.

Indications of whether tensions are due to underestimated hadronic effects or new physics.

Analysis of impact of different form factor calculations and bin choices.

Abstract

We present a critical assessment of the present $B$ anomalies in the exclusive $b \to s \ell\ell$ mode based on the QCD factorisation (QCDf) approach. In particular, we analyse the impact of different local form factor calculations and of the largest bin in the low-$q^2$ region. We also present a model-independent analysis of the new results of the LHCb and CMS experiments on the $B \to K^* \mu^+\mu^-$ angular observables. In addition, we update the global fit by including all $b \to s$ observables incorporating the new data from CMS and LHCb. In these analyses, we use 10% or higher guesstimates of the non-factorisable power corrections as additional uncertainties, serving as a placeholder for robust estimates of these contributions. Updating earlier results, we also analyse the combined LHCb and CMS data on the $B \to K^* \mu^+\mu^-$ angular observables using data-driven approaches to find indications whether these tensions between the QCDf predictions and the present data are due to underestimated subleading hadronic contributions or due to new physics effects.