A spreadsheet with the breakdown of the errors is available.

For averages not shown here see http://www.slac.stanford.edu/xorg/hfag/semi/winter05/winter05.shtml

The procedure for performing the average is documented in a brief note on averaging. There have been several changes from what was done in previous HFAG semileptonic averages.

The input files for the average are linked below. To summarize briefly, all theoretical uncertainties are considered to be correlated, as are the uncertainties on the modeling of b -> clnu and b -> ulnu decays. Experimental uncertainties (particle identification, reconstruction efficiencies, etc.) are taken as correlated amongst measurements from the same experiment, but not correlated across experiments. The set of results averaged have negligeable statistical correlations. Variations on the assumptions of which experimental errors were taken as correlated were considered; they have no significant impact on the average. If one fails to account for the dependence of the quoted errors on the measured values, the resulting average is biased low by -0.3 sigma.

The errors in the tables are experimental (statistical and systematic) and external (theoretical and HQ parameter uncertainties). The average B lifetime used was 1.604 ps.

The following values use HQ parameter input from a global fit to
both b -> c l nu and b -> s g moments in the kinetic
scheme, which gives parameters
m_{b} = 4.60 +- 0.04 GeV and mu_{pi}^{2}=0.20
+- 0.04 GeV^{2} (hep-ph/0507253).
The details of the fit are here.

These results are similar to those obtained in the 1S scheme in Phys. Rev. D70:094017, 2004 ( hep-ph/0408002). Work is in progress in HFAG to update the 1S fits using the latest set of moments measurements.

Experiment | Value [10^{-3}] |
Parameters | References | Remarks |
---|---|---|---|---|

CLEO (endpoint) | 3.93 +/- 0.46 +/- 0.33 | input | Phys.Rev.Lett.88:231803,2002 | 2.1 < p < 2.6, Vub redetermined from partial BF |

BELLE (endpoint) | 4.82 +/- 0.45 +/- 0.31 | input | preliminary (hep-ex/0504046) | 1.9 < p < 2.6 |

BABAR (endpoint) | 4.20 +/- 0.34 +/- 0.30 | input | preliminary (hep-ex/0408075) | 2.0 < p < 2.6, Vub redetermined from partial BF |

BABAR (E_{e}, q^{2}) | 4.00 +/- 0.27 +/- 0.35 | input | preliminary (hep-ex/0506036) | (E_{e}-q^{2}) |

BELLE m_{X} | 4.03 +/- 0.27 +/- 0.25 | input | preliminary (hep-ex/0505088) | m_{X}, BRECO tag; other methods (m_{X}-q^{2}
and P_{} not used) |

BELLE sim. ann. (m_{X}, q^{2}) | 4.32 +/- 0.46 +/- 0.29 | input | Phys.Rev.Lett.92:101801,2004 (hep-ex/0311048) | m_{X} - Q^{2}, tag with annealing method |

BABAR (m_{X}, q^{2}) | 4.70 +/- 0.34 +/- 0.31 | input | preliminary (hep-ex/05NNNNN) | m_{X}-q^{2}, BRECO tag |

Average +/- exp +/- (mb,theory) |
4.39 +/- 0.20 +/- 0.27 |
chi2/dof = 6.4/6 (CL = 0.38) |
Plots: eps gif | HQ parameter input from b to c l nu and b to s gamma moments |

+-2.3_{stat}
+-2.5_{exp}
+-2.1_{b2c model}
+-2.1_{b2u model}
+-4.5_{HQ param}
+-3.6_{sub SF}
+-1.9_{WA} = +-7.5_{tot}

where the errors correspond to statistics, experimental systematics,
the
modeling of b -> c l nu and b -> u l nu decays, the HQ parameters
m_{b} and mu_{pi}^{2}, subleading shape
functions
and Weak Annihilation.

The numbers below use input on the heavy quark parameters m_{b}
and mu_{pi}^{2} from based on global fits to b -> c l nu
moments in the kinetic scheme, translated
into the shape-function mass scheme to give
m_{b} = 4.66 +- 0.08 GeV
mu_{pi}^{2}=0.19 +- 0.05 GeV^{2} with
correlation rho=-0.4.
The details of the fit are here.

Experiment | Value [10^{-3}] |
Parameters | References | Remarks |
---|---|---|---|---|

CLEO (endpoint) | 3.61 +/- 0.42 +/- 0.47 | input | Phys.Rev.Lett.88:231803,2002 | 2.1 < p < 2.6, Vub redetermined from partial BF |

BELLE (endpoint) | 4.52 +/- 0.42 +/- 0.43 | input | preliminary (hep-ex/0504046) | 1.9 < p < 2.6 |

BABAR (endpoint) | 3.87 +/- 0.31 +/- 0.43 | input | preliminary (hep-ex/0408075) | 2.0 < p < 2.6, Vub redetermined from partial BF |

BABAR (E_{e}, q^{2}) | 3.70 +/- 0.25 +/- 0.49 | input | preliminary (hep-ex/0506036) | (E_{e}-q^{2}) |

BELLE m_{X} | 3.81 +/- 0.25 +/- 0.36 | input | preliminary (hep-ex/0505088) | m_{X}, BRECO tag; other methods (m_{X}-q^{2}
and P not used) |

BELLE sim. ann. (m_{X}, q^{2}) | 4.11 +/- 0.43 +/- 0.40 | input | Phys.Rev.Lett.92:101801,2004 (hep-ex/0311048) | m_{X} - Q^{2}, tag with annealing method |

BABAR (m_{X}, q^{2}) | 4.47 +/- 0.32 +/- 0.43 | input | preliminary (hep-ex/0507017) | m_{X}-q^{2}, BRECO tag |

Average +/- exp +/- (mb,theory) |
4.23 +/- 0.20 +/- 0.39 |
chi2/dof = 4.5/6 (CL = 0.61) |
Plots: eps gif | HQ parameter input from b to c l nu moments only |

+-2.5_{stat}
+-2.5_{exp}
+-2.3_{b2c model}
+-2.0_{b2u model}
+-8.2_{HQ param}
+-3.7_{sub SF}
+-1.8_{WA} = +-10.3_{tot}

where the errors correspond to statistics, experimental systematics, the
modeling of b -> c l nu and b -> u l nu decays, the HQ parameters
m_{b} and mu_{pi}^{2}, subleading shape functions
and Weak Annihilation.

Experiment / Mode | BF [10^{-4}] |
BF(q^{2}>16 GeV^{2}) [10^{-4}] |
Reference |
---|---|---|---|

BABAR SL tag: B ^{+} \rightarrow \pi^{0} l^{+} \nu \times 2\tau_{0}/\tau_{+} | 3.31 +/- 0.68 +/- 0.42 | NA | (1.80+-0.37+-0.23) Preliminary, SL tag (hep-ex/0506065) (input) |

BABAR Breco tag: B ^{+} \rightarrow \pi^{0} l^{+} \nu \times 2\tau_{0}/\tau_{+} | 1.68 +/- 0.52 +/- 0.24 | NA | (0.91+-0.28+-0.14) Preliminary, Breco tag (ICHEP conference paper) (input) |

BABAR SL tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu | 1.02 +/- 0.25 +/- 0.13 | 0.21 +/- 0.14 +/- 0.06 | Preliminary, SL tag (hep-ex/0506064) (input) |

Belle SL tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu | 1.79 +/- 0.28 +/- 0.20 +/- 0.03 | 0.46 +/- 0.17 | preliminary, SL tag (hep-ex/0408145) (input) |

BABAR Breco tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu | 0.89 +/- 0.34 +/- 0.12 | NA | Preliminary, Breco tag (ICHEP conference paper) (input) |

CLEO untagged: B \rightarrow \pi l^{+} \nu | 1.32 +/- 0.18 +/- 0.11 | 0.25 +/- 0.09 +/- 0.05 | Phys. Rev. D 68, 072003 (2003) (input) |

BABAR untagged: B \rightarrow \pi l^{+} \nu | 1.38 +/- 0.10 +/- 0.18 | 0.49 +/- 0.05 +/- 0.07 | Preliminary, nu reco (CKM2005 workshop talk) (input) |

Average: B ^{0} \rightarrow \pi^{-} l^{+} \nu |
1.36 +/- 0.11 |
0.396 +/- 0.054 |
Plots: eps gif chi2/dof = 11.2/6 (CL = 0.083) |

Using the partial BF for q^{2}> 16 GeV^{2} and
the FNAL04 calculation (hep-lat/0409116) of the form factor gives
|V_{ub}| = (3.75 +/- 0.27 +0.64 -0.42) 10^{-3},
where the first error is experimental and the second due to the
normalization unceratainty in the form factor calculation. With
the HPQCD calculation (hep-lat/0408019) of the form factor,
|V_{ub}| = (4.45 +/- 0.32 +0.69 -0.47) 10^{-3}.

A determination of |Vub| using
the region at low q^{2} along with LCSR calculations is in progress,
as is the use of methods that use the full q^{2} range.

Experiment | Mode | BF [10^{-4}] |
Reference |
---|---|---|---|

CLEO | B^{+}-> eta l^{+} nu |
0.84 +/-0.31 +0.16 +/-0.09 | Phys. Rev. D 68, 072003 (2003) |

CLEO | B^{0}-> rho^{-} l^{+} nu |
2.69 +/-0.41 +0.35/-0.40 +/-0.50 | Phys. Rev. D 61, 052001 (2000) |

BABAR | B^{0}-> rho^{-} l^{+} nu |
2.57 +/-0.52 +/-0.59 | Preliminary, Breco tag (ICHEP conference paper) |

BABAR | B^{0}-> rho^{-} l^{+} nu |
3.29 +/-0.42 +/-0.47 +/-0.60 | Phys. Rev. Lett. 90, 181801 (2003) |

CLEO | B^{0}-> rho^{-} l^{+} nu |
2.17 +/-0.34 +0.47/-0.54 +/-0.41 +/-0.01 | Phys. Rev. D 68, 072003 (2003) |

Belle | B^{0}-> rho^{-} l^{+} nu |
2.54 +/-0.78 +/-0.85 +/-0.30 | preliminary (hep-ex/0408145) |

BABAR | B^{0}-> rho^{-} l^{+} nu |
2.14 +/-0.21 +/-0.51 +/-0.28 | Preliminary, nu reco (CKM2005 workshop talk) |

Belle | B^{+}-> omega l^{+} nu |
1.3 +/-0.4 +/-0.2 +/-0.3 | Phys. Rev. Lett. 93:131803 (2004) |

Last update: 2005/06/29 Bob Kowalewski