Impact on $L$-observables of a new combined analysis of $B_{d,s}\to K^{(*)}$ form factors

TL;DR

This paper analyzes how a combined approach to $B_{d,s} o K^{(*)}$ form factors influences $L$-observables, reducing uncertainties and refining Standard Model predictions with updated lattice QCD and sum rule data.

Contribution

It introduces a comprehensive analysis of $B_{d,s} o K^{(*)}$ form factors, providing precise results and demonstrating their significant impact on $L$-observables and New Physics interpretations.

Findings

Updated form factors significantly alter $L$-observable predictions.

Inclusion of lattice QCD data affects the Standard Model estimates.

Revised predictions influence New Physics interpretations.

Abstract

We explore the impact of a combined analysis of $B_{d,s}\to K^{(*)}$ form factors on a set of $L$-observables. The $L$-observables are constructed from ratios of branching fractions in $B_{s}\to VV,PP,PV$ versus $B_d \to VV,PP,PV$ decays with $P=K^0,\bar{K}^0$ and $V=K^{*0},\bar{K}^{*0}$, thereby partially reducing their hadronic uncertainties. We show the change of the Standard Model predictions of the $L$-observables under different determinations of the ratio of the relevant form factors (with correlations) including lattice QCD data and a novel light-cone sum rule analysis. In addition, we provide precise results for all $B_{d,s} \to K^{(*)}$ form factors in machine-readable files. We find that the inclusion of our up-to-date results, as well as the use or omission of lattice QCD data for the form factors, has a significant impact on the $L$-observables. We also discuss how the New Physics interpretation is affected by the updated form factors and present revised predictions for the mechanism identified in our analysis of $B \to VP$ decays, now employing more suitable new experimental observables defined in this paper.