Purpose

This HFLAV Rare B decays group provides the latest results and averages of branching fractions (BF), polarization
fractions, partial rate asymmetries (A_CP) and other observables of b-hadron decays to final states that do not contain charm hadrons or charmonium mesons, except for a few lepton-flavour- and lepton-number-violating decays reported in the section Rare decays of B⁰ and B⁺ mesons with photons and/or leptons (in the html version of the averages: Electroweak radiative B decays)

The treatment of intermediate charm or charmonium states differs between observables and sometimes among results for the same observable. In the latter case, when these results are averaged, we indicate the differences by footnotes.

The organisation of the tables

Four categories of B⁰ and B⁺ decays are reported: mesonic (i.e., final states containing only mesons), baryonic (hadronic final states with baryon-antibaryon pairs), radiative (including a photon or a lepton-antilepton pair) and semileptonic/leptonic (including/only leptons). We also report measurements of B⁰_s, B_c and b-baryon decays, and measurements of final-state polarization in b-hadron decays.
Results of CKM-matrix parameters obtained from A_CP measurements are listed and described by the HFLAV Unitary triangle angles group.
Measurements included in our averages are those supported with public notes, including journal papers, conference contributed papers, preprints or conference proceedings, except when a result has not led to a journal publication after an extended period of time.

Tables are available for

Branching fractions of charmless mesonic B⁰ and B^± meson decays
Branching fractions of charmless baryonic B⁰ and B^± meson decays
Branching fractions of charmless decays of b-baryons
Branching fractions of charmless mesonic B⁰_s meson decays
Branching fractions of charmless mesonic B_c meson decays
Branching fractions and other observables of radiative and leptonic B⁰ and B^± meson decays, including LFV and LNV modes
Direct A_CP in b-hadron decays
Polarization measurements in b-hadron decays

At the end of some of these sections, we give a list of results that were not included in the tables. Typical cases are the measurements of distributions, such as differential branching fractions or longitudinal polarizations, which are measured in different binning schemes by the different collaborations, and thus cannot be directly used to obtain averages.

Method

Changes have been introduced to the averaging method as from the update corresponding to the HFLAV 2021 paper.

Details on the averaging method, may be found in Chapter 3 - Averaging methodology of the latest HFLAV publication. The preamble of our chapter, which may be also found in the pdf version of the tables of each update (for instance here) contains useful information about the input of the averages and and the conventions used in the tables.

Averages

As from the update corresponding to the HFLAV 2021 publication, we have been using a new framework, with improvements both in the averaging method and the presentation of the results.

End of December 2024 (latest)

These pages contain tables and plots that include results put on the arXiv and InspireHEP until the end of May 2024. The PDG averages correspond to PDG 2023 [R.L. Workman et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2022, 083C01 (2022) and 2023 update].