Exclusive b \to s (d) ll Decays

TL;DR

This paper reports on BABAR's measurements of rare B meson decays, revealing unexpected isospin asymmetries and deviations from the Standard Model, along with angular analysis and search results for related processes.

Contribution

It provides new experimental measurements of B -> K(*) l+ l- decays, highlighting significant isospin asymmetries and deviations from Standard Model predictions.

Findings

Large isospin asymmetries observed in B decays.

3.9 sigma deviation from SM in combined data.

Angular analysis results for B -> K* l+ l-.

Abstract

New BABAR measurements are presented for the exclusive rare decays B -> K(*) l+ l- including branching fractions, isospin asymmetries, direct CP violation, and lepton flavor universality for dilepton masses below and above the J/psi resonance. Unexpectedly large isospin asymmetries are observed in both K l+l- and K* l+ l- decays. For the combined K l+l- and K* l+l- data a 3.9 sigma significant deviation from the SM prediction is found. Furthermore, recent BABAR results from an angular analysis in B -> K* l+l- are reported in which both the K* longitudinal polarization and the lepton forward-backward asymmetry are measured for dilepton masses below and above the J/psi resonance. Finally, results of recent searches for B -> pi l+l-$ from Belle and B -> K(*) nu anti nu$ from BABAR are summarized.