CERN Accelerating science

Rare B decays

To access directly our latest averages click here

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Purpose

This HFLAV Rare B decays group provides the latest results and averages of branching fractions (BF), polarization 
fractions, partial rate asymmetries (ACP) 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 B0s, Bc and b-baryon decays, and measurements of final-state polarization in b-hadron decays.
Results of CKM-matrix parameters obtained from ACP 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 B0s meson decays
  • Branching fractions of charmless mesonic Bc meson decays

  • Branching fractions and other observables of radiative and leptonic B0 and B± meson decays, including LFV and LNV modes

  • Direct ACP 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 April 2023 (latest)

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

The rare-decays averages are available here.
Details about the input and average of each observable are accessible via clickable links.

All the results that have been added or modified in the present update are listed here.
This page groups all types of observables (BFs, ACP, ratios of BFs...).

The pdf version of the rare-decays tables and plots, including an introduction with further details about the averaging method and conventions used in the tables, is available here.

*New* The rare-decays average in an alternative presentation is available here.
The user may find decay modes by choosing initial- and final-state particles. It is also possible to select several modes and present them in the same plot.

 

End of January 2023

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

The rare-decays averages are available here.
Details about the input and average of each observable are accessible via clickable links.

All the results that have been added or modified in the present update are listed here.
This page groups all types of observables (BFs, ACP, ratios of BFs...).

The pdf version of the rare-decays tables and plots, including an introduction with further details about the averaging method and conventions used in the tables, is available here.

 

End of October 2022

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

The rare-decays averages are available here.
Details about the input and average of each observable are accessible via clickable links.

All the results that have been added or modified in the present update are listed here.
This page groups all types of observables (BFs, ACP, ratios of BFs...), grouped by papers.

The pdf version of the rare-decays tables and plots, including an introduction with further details about the averaging method and conventions used in the tables, is available here.

 

ICHEP 2022

The ICHEP 2022 pages contain tables and plots that include results put on the arXiv until the end of June 2022. They also cover results presented in ICHEP 2022. The PDG averages correspond to PDG 2022 [R.L. Workman et al. (Particle Data Group), to be published in Prog. Theor. Exp. Phys. 2022, 083C01 (2022)].

The rare-decays averages are available here.
Details about the input and average of each observable are accessible via clickable links.

The pdf version of the rare-decays tables and plots, including an introduction with further details about the averaging method and conventions used in the tables, is available here.

 

HFLAV 2021 publication

The HFLAV 2021 publication pages contain tables and plots that include results put on the arXiv until the end of June 2021.  In most of the tables, the averages are compared to those from PDG 2021. The averages were performed for the first time using our new framework.

The rare-decays averages are available here.
Details about the input and average of each observable are accessible via clickable links.

The arXiv version of the publication is available here.

The pdf version of the rare-decays tables and plots, including an introduction with further details about the averaging method and conventions used in the tables, is available here.

 

Earlier versions of our tables

April 2019

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

The April 2019 pages contain tables and plots that include results put on the arXiv until the end of the April 2019. They cover results presented in the winter conferences of 2019. The PDG results have been updated to those of PDG live (end of 2017), as from the December 2017 pages.

May 2018

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

December 2017

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

August 2017

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

November 2016

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

October 2016

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

ICHEP 2016

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons BcWhat's new

2014

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs b-baryons

2013

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs

2012

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs

2011

Charmless mesonic Radiative and leptonic Baryonic Acp VV polarization Bs

 

Older results have been removed, but can be obtained upon request.
The tables:

Charmless mesonic , Radiative and leptonic , Baryonic , Acp , VV polarization, Bs,

exist for:

ICHEP 2010, Winter 2010, LepPho 2009, Winter 2009, ICHEP 2008, Winter 2008, LepPho 2007, Winter 2007, ICHEP 2006, Winter 2006, LepPho 2005, Winter 2005, ICHEP 2004, Winter 2004, LepPho 2003, Winter 2003, PDG 2002.

 

Group members

See the About us page.


This page is maintained by Eli Ben-Haim