B -> K(*) l+ l- @ Low Recoil and Physics Implications

TL;DR

This paper discusses recent theoretical advances in analyzing rare B-decays at low recoil, highlighting how angular analysis and form factor ratios can test the Standard Model with reduced uncertainties.

Contribution

It introduces methods to suppress corrections and extract form factor ratios from data, improving the precision of tests of the Standard Model and hadronic physics in B-decays.

Findings

Form factor ratios can be extracted from current data.

Lattice QCD and sum rule results are consistent across kinematic ranges.

Angular analysis provides simultaneous access to electroweak and hadronic physics.

Abstract

This talk covers recent theoretical progress in exclusive semileptonic rare B-decays at low hadronic recoil. The efficient parametric suppression of the 1/mb corrections in this region provides opportunities to probe the Standard Model and beyond at precision level. Notably, angular analysis allows to simultaneously access electroweak flavor physics and hadronic matrix elements, the latter of which constitute the leading source of theoretical uncertainty. Ratios of B ->K* form factors can already be extracted from present data. A comparison with existing theoretical determinations by lattice QCD and light cone sum rules gives a consistent picture over the whole kinematic range. In the future improved analyses will advance our understanding of non-perturbative methods for QCD and of |Delta B|=1 transitions.