Angular analysis of B --> V (--> P_1 P_2) l^+ l^- decays

TL;DR

This paper explores the angular analysis of rare B-meson decays into four-body final states to test the Standard Model and search for New Physics, proposing methods to reduce uncertainties and validate form factors.

Contribution

It introduces new observables and combinations for B-meson decay analysis that minimize hadronic uncertainties and facilitate tests of short-distance physics and form factors.

Findings

Identification of observables for CP asymmetries

Methods to reduce hadronic uncertainties

Proposals for testing lattice QCD form factors

Abstract

The angular analysis of exclusive rare B-meson decays via intermediate vector mesons V into 4-body final states of two pseudo-scalars P_1, P_2 and a pair of light leptons l = e, mu offers a large set of observables. They can be used to test the electroweak short-distance couplings in the Standard Model and to search for New Physics. The two kinematic regions of low and high dilepton mass depend on short-distance physics in complementary ways and can be expanded in powers of Lambda_QCD/m_b. These expansions guide towards suitable combinations of observables allowing to i) reduce the hadronic uncertainties in the extraction of the short-distance couplings or ii) test the lattice QCD (B -> V) form factors in short-distance independent combinations. Several such possibilities of CP-averaged and CP-asymmetric (T-even and T-odd) quantities are presented for B_d^0 --> K^*0 (-> K pi) l^+ l^- and time-integrated CP-asymmetries without tagging for (anti-B_s, B_s) --> phi (--> K^- K^+) l^+ l^- decays in view of the latest B-factory and CDF results and the forthcoming LHCb measurements.