Updates of Semileptonic Results for Summer 2014

This web page contains the updated averages of the HFAG semileptonic group for the PDG 2014 Update (common parameter file).

B -> D*lnu Exclusive

etaEW F(1) |Vcb| from B -> D*lnu

In the parameterization of Caprini et al. [Nucl. Phys. B530, 153 (1998)], the decay B -> D*lnu is described by four quantities: etaEW F(1) |Vcb|, rho2, R1 and R2. The following average is the result of a four-dimensional global fit of these four parameters to the measurements listed below. The values reported for each experiment have been rescaled to the most recent values of the external parameters (B lifetimes, D meson branching fractions) and to the values of R1 and R2 found by the global fit, R1(1)=1.406 +/- 0.033 and R2(1)=0.853 +/- 0.020. The fit assumes isospin symmetry.
Experiment etaEW F(1) |Vcb| (rescaled) [10-3] rho2 (rescaled) Correlation (stat/syst/total) Parameters Remarks
ALEPH 31.23 +/- 1.80 +/- 1.30 0.493 +/- 0.228 +/- 0.144 0.94/0.67/0.85 input     parameters Phys.Lett.B395:373-387,1997
CLEO 39.94 +/- 1.23 +/- 1.62 1.367 +/- 0.085 +/-0.086 0.91/0.83/0.86 input     parameters Phys.Rev.Lett.89:081803,2002
OPAL excl 36.50 +/- 1.60 +/- 1.49 1.234 +/- 0.212 +/- 0.145 0.95/0.45/0.75 input     parameters Phys.Lett.B482:15-30,2000
OPAL partial reco 37.14 +/- 1.19 +/- 2.36 1.152 +/- 0.145 +/- 0.294 0.77/0.78/0.78 input     parameters Phys.Lett.B482:15-30,2000
DELPHI partial reco 35.32 +/- 1.40 +/- 2.33 1.174 +/- 0.126 +/- 0.377 0.94/0.68/0.70 input     parameters Phys.Lett.B510:55-74,2001
DELPHI excl 36.10 +/- 1.70 +/- 1.97 1.081 +/- 0.142 +/- 0.152 0.89/0.80/0.84 input     parameters Eur.Phys.J.C33:213-232,2004
BELLE 34.60 +/- 0.17 +/- 1.02 1.212 +/- 0.034 +/- 0.009 0.63/-0.11/0.07 input     parameters Phys.Rev.D82:112007,2010
BABAR excl 33.94 +/- 0.30 +/- 0.99 1.185 +/- 0.048 +/- 0.029 0.27/0.02/0.08 input     parameters Phys.Rev.D77:032002,2008
BABAR D*0 35.22 +/- 0.59 +/- 1.33 1.128 +/- 0.058 +/- 0.055 0.90/0.37/0.50 input     parameters Phys.Rev.Lett.100:231803,2008
BABAR global fit 35.76 +/- 0.20 +/- 1.10 1.193 +/- 0.020 +/- 0.061 0.38/0.85/0.81 input     parameters Phys.Rev.D79:012002,2009
Average 35.81 +/- 0.11 +/- 0.44 1.207 +/- 0.015 +/- 0.021 0.49/0.32/0.32 chi2/dof = 30.0/23 (CL = 0.150) eps 1  pdf 1  eps 2  pdf 2 

Exclusive Branching Fraction: B0 -> D*-lnu (using both isospin states)

These branching fractions have been calculated from the values of etaEW F(1) |Vcb|, rho2, R1 and R2 obtained by the global four-dimensional fit described above.
Experiment BF (rescaled) [%] Remarks
ALEPH 5.35 +/- 0.25 +/- 0.31 Phys.Lett.B395:373-387,1997
CLEO 5.62 +/- 0.18 +/- 0.26 Phys.Rev.Lett.89:081803,2002
OPAL excl 5.05 +/- 0.19 +/- 0.42 Phys.Lett.B482:15-30,2000
OPAL partial reco 5.46 +/- 0.25 +/- 0.52 Phys.Lett.B482:15-30,2000
DELPHI partial reco 4.88 +/- 0.13 +/- 0.72 Phys.Lett.B510:55-74,2001
DELPHI excl 5.35 +/- 0.20 +/- 0.37 Eur.Phys.J.C33:213-232,2004
BELLE 4.56 +/- 0.03 +/- 0.26 Phys.Rev.D82:112007,2010
BABAR excl 4.54 +/- 0.04 +/- 0.25 Phys.Rev.D77:032002,2008
BABAR D*0 4.97 +/- 0.07 +/- 0.34 Phys.Rev.Lett.100:231803,2008
BABAR global fit 4.95 +/- 0.02 +/- 0.20 Phys.Rev.D79:012002,2009
Average 4.93 +/- 0.01 +/- 0.11 chi2/dof = 30.0/23 (CL = 0.150)   eps  pdf

Exclusive Branching Fraction: B+ -> D*0bar lnu

The average BF is the result of a one-dimensional fit to the measurements listed.
Experiment BF (rescaled) [%] Parameters Remarks
CLEO 6.60 +/- 0.20 +/- 0.39 input     parameters Phys.Rev.D67:032001,2003
BABAR tagged 5.74 +/- 0.15 +/- 0.30 input     parameters Phys.Rev.Lett.100:151802,2008
BABAR untagged 5.36 +/- 0.08 +/- 0.40 input     parameters Phys.Rev.Lett.100:231803,2008
BABAR global fit 5.42 +/- 0.02 +/- 0.21 input     parameters Phys.Rev.D79:012002,2009
Average 5.69 +/- 0.02 +/- 0.19 chi2/dof = 9.0/3 (CL = 0.0294) eps  pdf


B -> Dlnu Exclusive

etaEW G(1) |Vcb| from B -> Dlnu

In the parameterization of Caprini et al. [Nucl. Phys. B530, 153 (1998)], the decay B -> Dlnu is described by two quantities: etaEW G(1) |Vcb| and rho2. The following average is the result of a two-dimensional global fit of these two parameters to the measurements listed below. The values reported for each experiment have been rescaled to the most recent values of the external parameters (B lifetimes, D meson branching fractions). The fit assumes isospin symmetry.
Experiment etaEW G(1) |Vcb| (rescaled) [10-3] rho2 (rescaled) Correlation (stat/syst/total) Parameters Remarks
ALEPH 38.66 +/- 11.80 +/- 5.19 0.942 +/- 0.980 +/- 0.272 0.98/1.00/0.97 input     parameters Phys.Lett.B395:373-387,1997
CLEO 44.88 +/- 5.96 +/- 3.25 1.270 +/- 0.220 +/- 0.119 0.95/0.40/0.83 input     parameters Phys.Rev.Lett.82:3746,1999
BELLE 40.96 +/- 4.39 +/- 5.03 1.120 +/- 0.190 +/- 0.111 0.96/0.19/0.62 input     parameters Phys.Lett.B526:258-268,2002
BABAR global fit 43.25 +/- 0.80 +/- 2.07 1.201 +/- 0.040 +/- 0.057 0.96/0.86/0.85 input     parameters Phys.Rev.D79:012002,2009
BABAR tagged 42.54 +/- 1.88 +/- 1.02 1.177 +/- 0.088 +/- 0.057 0.95/0.44/0.82 input     parameters Phys.Rev.Lett.104:011802,2010
Average 42.65 +/- 0.72 +/- 1.35 1.185 +/- 0.035 +/- 0.041 0.96/0.79/0.82 chi2/dof = 0.5/8 (CL = 1.000) eps 1  pdf 1  eps 2  pdf 2 

Exclusive Branching Fraction: B0 -> D-lnu (using both isospin states)

These branching fractions have been calculated from the values of etaEW G(1) |Vcb| and rho2 obtained by the global two-dimensional fit described above.
Experiment BF (rescaled) [%] Remarks
ALEPH 2.15 +/- 0.18 +/- 0.45 Phys.Lett.B395:373-387,1997
CLEO 2.19 +/- 0.16 +/- 0.35 Phys.Rev.Lett.82:3746,1999
BELLE 2.08 +/- 0.12 +/- 0.52 Phys.Lett.B526:258-268,2002
BABAR global fit 2.16 +/- 0.03 +/- 0.13 Phys.Rev.D79:012002,2009
BABAR tagged 2.14 +/- 0.11 +/- 0.08 Phys.Rev.Lett.104:011802,2010
Average 2.13 +/- 0.03 +/- 0.09 chi2/dof = 0.5/8 (CL = 1.000)   eps  pdf

Exclusive Branching Fraction: B0 -> D- lnu

The average BF is the result of a one-dimensional fit to the measurements listed.
Experiment BF (rescaled) [%] Parameters Remarks
ALEPH 2.28 +/- 0.18 +/- 0.35 input     parameters Phys.Lett.B395:373-387,1997
CLEO 2.13 +/- 0.13 +/- 0.15 input     parameters Phys.Rev.Lett.82:3746,1999
BELLE 2.11 +/- 0.12 +/- 0.39 input     parameters Phys.Lett.B526:258-268,2002
BABAR 2.22 +/- 0.11 +/- 0.12 input     parameters Phys.Rev.Lett.100:151802,2008
Average 2.19 +/- 0.06 +/- 0.10 chi2/dof = 0.2/3 (CL = 0.973) eps  pdf

Exclusive Branching Fraction: B+ -> D0bar lnu

The average BF is the result of a one-dimensional fit to the measurements listed.
Experiment BF (rescaled) [%] Parameters Remarks
CLEO 2.20 +/- 0.13 +/- 0.17 input     parameters Phys.Rev.Lett.82:3746,1999
BABAR 2.29 +/- 0.09 +/- 0.09 input     parameters Phys.Rev.Lett.100:151802,2008
Average 2.27 +/- 0.07 +/- 0.08 chi2/dof = 0.1/1 (CL = 0.721) eps  pdf


B -> D** lnu Exclusive

Exclusive Branching Fraction: B- -> D1(D*-pi-)lnu

We report the average for the product of branching fractions of B- -> D1(D*-pi)lnu and D1 -> D*+pi-. Apart for the CLEO,BELLE and BABAR results, the other measurements are for the final state D1(D*-pi-)X. We assume that no particle is left in the X system.
Experiment BF (rescaled) [%] Parameters Remarks
ALEPH 0.440+/- 0.098+/- 0.068 input     parameters Z.Phys. C 73:601,1997 [Z.Phys.C73]
OPAL 0.578 +/- 0.210+/- 0.101 input     parameters Eur.Phys. J.C 30:467,2003 [hep-ex/0301018]
CLEO 0.354 +/- 0.085+/- 0.056 input     parameters Phys.Rev.Lett.80:4127,1998 [hep-ex/9708035]
D0 0.215 +/- 0.018+/- 0.035 input     parameters Phys.Rev.Lett.95:171803,1995 [hep-ex/0507046]
BELLE tagged B+ 0.443 +/- 0.070+/- 0.059 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BELLE tagged B0 0.612 +/- 0.200+/- 0.077 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR tagged 0.278 +/- 0.030+/- 0.028 input     parameters Phys.Rev.Lett.101:261802,2008 [arXiv:0808.0528 [hep-ex]]
BABAR untagged B+ 0.295 +/- 0.017+/- 0.016 input     parameters Phys.Rev.Lett.103:051803,2009 [arXiv:0808.0333 [hep-ex]]
BABAR untagged B0 0.299 +/- 0.026+/- 0.027 input     parameters Phys.Rev.Lett.103:051803,2009 [arXiv:0808.0333 [hep-ex]]
Average 0.285 +/- 0.011 +/- 0.14 chi2/dof = 13/8 (CL = 11.1%) eps pdf gif

Exclusive Branching Fraction: B- -> D2(D*-pi-)lnu

We report the average for the product of branching fractions of B- -> D2(D*-pi)lnu and D2 -> D*+pi-. Apart for the CLEO, BELLE and BABAR results, the other measurements are for the final state D2(D*-pi-)X. We assume that no particle is left in the X system. The BABAR tagged measurement have been transalted in a result on D2* -->D*pi decay modes, assuming BF(D2->Dpi)/BF(D2->D*pi)=1.54+/-0.14.
Experiment BF (rescaled) [%] Parameters Remarks
CLEO 0.056 +/- 0.066+/- 0.011 input     parameters Phys.Rev.Lett.80:4127,1998 [hep-ex/9708035]
D0 0.087 +/- 0.018+/- 0.020 input     parameters Phys.Rev.Lett.95:171803,2005 [hep-ex/0507046]
BELLE tagged 0.190 +/- 0.060+/- 0.025 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR tagged 0.076 +/- 0.013 +/- 0.009 input     parameters Phys.Rev.Lett.101:261802,2008 [arXiv:0808.0528 [hep-ex]]
BABAR untagged B+ 0.090 +/- 0.009+/- 0.007 input     parameters Phys.Rev.Lett.103:051803,2009 [arXiv:0808.0333 [hep-ex]]
BABAR untagged B0 0.067 +/- 0.010+/- 0.004 input     parameters Phys.Rev.Lett.103:051803,2009 [arXiv:0808.0333 [hep-ex]]
Average 0.078 +/- 0.007 +- 0.004 chi2/dof = 5.6/5 (CL = 34.7%) eps pdf gif

Exclusive Branching Fraction: B- -> D1'(D*-pi-)lnu

We report the average for the product of branching fractions of B- -> D1'(D*-pi)lnu and D1' -> D*+pi-. The DELPHI measurement is for the final state D1'(D*-pi-)X. We assume that no particle is left in the X system.
Experiment BF (rescaled) [%] Parameters Remarks
DELPHI 0.74 +/- 0.17+/- 0.18 input     parameters Eur.Phys.J.C45:35-59,2006 [hep-ex/0510024]
BELLE tagged -0.03 +/- 0.06+/- 0.07 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR tagged 0.26 +/- 0.04 +/- 0.04 input     parameters Phys.Rev.Lett.101:261802,2008 [arXiv:0808.0528 [hep-ex]]
Average 0.13 +/- 0.03 +/- 0.02 chi2/dof = 18/2 (CL = 0.001) eps pdf gif

Exclusive Branching Fraction: B- -> D0*(D-pi-)lnu

We report the average for the product of branching fractions of B- -> D0*(D-pi)lnu and D0* -> D+pi-.
Experiment BF (rescaled) [%] Parameters Remarks
BELLE tagged B+ 0.25 +/- 0.04+/- 0.06 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BELLE tagged B0 0.23 +/- 0.08+/- 0.06 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR tagged 0.32 +/- 0.04 +/- 0.05 input     parameters Phys.Rev.Lett.101:261802, 2008 [arXiv:0808.0528 [hep-ex]]
Average 0.29 +/- 0.03 +/- 0.04 chi2/dof = 0.61/2 (CL = 74%) eps pdf gif

Exclusive Branching Fraction: B- -> D+ pi-lnu

The branching fractions are obtained by a 1-d fit to the missing mass in fully reconstructed events.
Experiment BF (rescaled) [%] Parameters Remarks
BELLE 0.42+/- 0.04+/- 0.05 input     parameters [Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR 0.42+/- 0.06+/- 0.03 input     parameters [Phys.Rev.Lett.100:151802, 2008 [arXiv:0712.3503 [hep-ex]]
Average 0.42+/- 0.05 chi2/dof = 0.01 (CL = 0.90) eps pdf gif

Exclusive Branching Fraction: B- -> D*+ pi-lnu

The branching fractions are obtained by a 1-d fit to the missing mass in fully reconstructed events.
Experiment BF (rescaled) [%] Parameters Remarks
BELLE 0.68+/- 0.08+/- 0.07 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR 0.57+/- 0.05+/- 0.04 input     parameters Phys.Rev.Lett.100:151802, 2008 [arXiv:0712.3503 [hep-ex]]
Average 0.60+/- 0.06 chi2/dof = 0.5 (CL = 0.52) eps pdf gif

Exclusive Branching Fraction: B0 -> D0 pi+lnu

The branching fractions are obtained by a 1-d fit to the missing mass in fully reconstructed events.
Experiment BF (rescaled) [%] Parameters Remarks
BELLE 0.43+/- 0.07+/- 0.05 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR 0.41+/- 0.08+/- 0.03 input     parameters Phys.Rev.Lett.100:151802, 2008 [arXiv:0712.3503 [hep-ex]]
Average 0.42+/- 0.06 chi2/dof = 0.04 (CL = 0.85) eps pdf gif

Exclusive Branching Fraction: B0 -> D*0 pi+ lnu

The branching fractions are obtained by a 1-d fit to the missing mass in fully reconstructed events.
Experiment BF (rescaled) [%] Parameters Remarks
BELLE 0.58+/- 0.21+/- 0.07 input     parameters Phys.Rev.D77:091503, 2008 [arXiv:0711.3252 [hep-ex]]
BABAR 0.46+/- 0.08+/- 0.04 input     parameters Phys.Rev.Lett.100:151802, 2008 [arXiv:0712.3503 [hep-ex]]
Average 0.48+/- 0.08 chi2/dof = 0.25 (CL = 0.62) eps pdf gif

B -> Xclnu Inclusive

Global fit in the kinetic scheme

Theory input

We use the predictions of the semileptonic width, the moments of the lepton energy spectrum and the moments of the hadronic mass spectrum squared in B -> Xclnu for different lepton energy thresholds obtained in JHEP 1109 (2011) 055.

Experimental input

These OPE expressions are fit to these B -> Xclnu moment measurements. The symbol 'n' indicates the order of the moment while 'c' indicates the value of the minimum lepton energy (in GeV). The n=0 lepton moment is the partial branching fraction of B -> Xclnu.

Experiment Hadron moments <MnX> Lepton moments <Enl> References
BaBar n=2 c=0.9,1.1,1.3,1.5
n=4 c=0.8,1.0,1.2,1.4
n=6 c=0.9,1.3 [1]
n=0 c=0.6,1.2,1.5
n=1 c=0.6,0.8,1.0,1.2,1.5
n=2 c=0.6,1.0,1.5
n=3 c=0.8,1.2 [1,2]
[1] Phys.Rev. D81 (2010) 032003
[2] Phys.Rev. D69 (2004) 111104
Belle n=2 c=0.7,1.1,1.3,1.5
n=4 c=0.7,0.9,1.3 [3]
n=0 c=0.6,1.4
n=1 c=1.0,1.4
n=2 c=0.6,1.4
n=3 c=0.8,1.2 [4]
[3] Phys.Rev. D75 (2007) 032005
[4] Phys.Rev. D75 (2007) 032001
CDF n=2 c=0.7
n=4 c=0.7 [5]
. [5] Phys.Rev. D71 (2005) 051103
CLEO n=2 c=1.0,1.5
n=4 c=1.0,1.5 [6]
. [6] Phys.Rev. D70 (2004) 032002
DELPHI n=2 c=0.0
n=4 c=0.0
n=6 c=0.0 [7]
n=1 c=0.0
n=2 c=0.0
n=3 c=0.0 [7]
[7] Eur.Phys.J. C45 (2006) 35-59

Results

The global fit determines the semileptonic B meson branching fraction, the quark masses mb and mc and the OPE parameters mu2pi, mu2G, rho3D and rho3LS. mu2G and rho3LS are constrained to (0.35 +/- 0.07) GeV2 and (-0.15 +/- 0.10) GeV3, respectively. The c-quark mass (defined in the MSbar scheme) is fixed to (0.986 +/- 0.013) GeV from Phys.Rev. D80 (2009) 074010. Refer to Phys.Rev. D89 (2014) 014022 for more details on the fit. From these parameters |Vcb| is calculated assuming an average B meson lifetime of (1.579 +/- 0.005) ps. The chi2 of the fit is 14.6 for 50-7 degrees of freedom.

Br(B -> Xclnu) (%) |Vcb| (10-3) mbkin (GeV) mu2pi (GeV2)
10.65 +/- 0.16 42.46 +/- 0.88 4.541 +/- 0.023 0.414 +/- 0.078 details

The following plots show the result of the fit in terms of the partial branching fraction (e0), the lepton energy (e1, e2, e3) and the hadronic mass squared (h1, h2, h3) moments. In all plots, the grey band is the theory prediction with total theory error. BaBar data are shown by circles, Belle by squares and other experiments (DELPHI, CDF, CLEO) by triangles. Filled symbols mean that the point was used in the fit. Open symbols are measurements that were not used in the fit.

Moment
e0 eps   pdf
e1 eps   pdf
e2 eps   pdf
e3 eps   pdf
h1 eps   pdf
h2 eps   pdf
h3 eps   pdf

|Vub| from inclusive semileptonic B decays

The results in this section are determined by comparing the measured partial branching fractions in selected regions of phase-space to theoretical calculations of the corresponding rates, which depends on |Vub|. The following theoretical calculations are used to extract |Vub|:

In the |Vub| averages only measurements for which the correlation is known are considered. They are either independent measurements or correlated measurements for which the correlation among the analyses is available (eg the BaBar B-Reco analyses). If the analyses are correlated but the correlation is not known, the analysis with the smallest error is considered.

No attempt is made to average values for |Vub| from the different theoretical models, but the results are presented independently per each scheme.

The procedure for performing the average is documented in [arXiv:0808.1297]

The input files for the average are linked in the tables with the averages. 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. Statistical correlations are also taken into account, when available.

The errors in the tables are experimental (statistical and systematic) and external (theoretical and HQ parameter uncertainties). The average B lifetime used is 1.582 ps. Final state radiation is included in all the measurements.

The input parameters for the different modes are coming from the global fit in the kinetic scheme, translated to the scheme needed per each model. For consistency among all the measurements, we choose the results coming from the fits to the b->clnu moments, with a constraint on the charm quark mass.

Determination of |Vub| (BLNP)   

The |Vub| values are obtained using the HQE input parameter:

obtained from the global fit in the kinetic scheme. The first error is the statistical error of the fit, the second is due to the scheme translation. The latter has been taken from hep-ph/0412241.

|Vub | (BLNP)
Experiment Value [10-3] Parameters References Remarks
CLEO (Ee) 4.28 ± 0.50 + 0.31 - 0.36 input Phys.Rev.Lett.88:231803,2002
[arXiv:hep-ex/0202019v1]
2.1 < Ee < 2.6
BELLE sim. ann. (mX, q2) 4.49 ± 0.47 + 0.28 - 0.30 input Phys.Rev.Lett.92:101801,2004
[arXiv:hep-ex/0311048v2]
Cut on mX<1.7 GeV, q2>8GeV2
tag with annealing method
BELLE (Ee) 4.93 ± 0.46 + 0.27 - 0.29 input Phys.Lett.B621:28-40 (2005)
[arXiv:hep-ex/0504046v2]
1.9 < Ee < 2.6
BABAR (Ee) 4.54 ± 0.26 + 0.27 - 0.33 input Phys.Rev.D73:012006,2006
[arXiv:hep-ex/0509040v2]
2.0 < Ee < 2.6
BABAR (Ee, shmax) 4.53 ± 0.22 + 0.33 - 0.38 input preliminary update (EPS2013) of
[arXiv:hep-ex/0506036v3]
Ee > 2.0, shmax < 3.5
BELLE multivariate (p*) 4.49 ± 0.27 + 0.20 - 0.22 input Phys.Rev.Lett.104:021801,2010
[arXiv:0907.0379v1 [hep-ex]]
BRECO tag; multivariate analysis.
Cut on lepton energy at 1 GeV
BABAR (mX<1.55) 4.30 ± 0.20 + 0.28 - 0.27 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX< 1.55 GeV
BABAR (mX<1.7) 4.04 ± 0.22 + 0.23 - 0.23 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX<1.7 GeV
BABAR (mX<1.7, q2>8) 4.30 ± 0.23 + 0.26 - 0.28 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at mX<1.7 GeV, q2>8 GeV2
BABAR (P+<0.66) 4.15 ± 0.25 + 0.28 - 0.27 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at P+<0.66 GeV
BABAR (p*>1GeV) 4.32 ± 0.24 + 0.19 - 0.21 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit (mX, q2), cut at p*>1GeV
BABAR (p*>1.3GeV) 4.32 ± 0.27 + 0.20 - 0.21 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit p*, cut at p*>1.3GeV
Average ± exp + th. - th. 4.45 ± 0.16 + 0.21 - 0.22 χ2/dof = 9.00/11
(CL = 0.62)
Plots: eps pdf gif mb input from global fit in the kinetic scheme

The full breakdown of the uncertainties on the average |Vub| above is (all errors quoted in percent):

positive errors: +2.0stat +1.7exp +1.2b2c model +1.9b2u model +2.6HQE param +0.1SF func +0.6sub SF +0.0WA +3.8matching = +5.8tot

negative errors: -2.1stat -1.8exp -1.2b2c model -1.8b2u model -2.7HQE param -0.3SF func -0.6sub SF -1.4WA -3.8matching = -5.9tot

where the fractions correspond to the statistical error (stat), the experimental systematics (exp), the modeling, e.g. branching fractions for exclusive decays, of b -> c l nu and b -> u l nu decays (b2c model and b2u model, respectively), the HQE parameters mb and μπ2 (HQE param), the functional form of the SF (ie the variation from the exponential to the Gaussian form of the SF, SF func), the subleading shape functions (sub SF), the variation of the matching scales (matching), and the Weak Annihilation (WA). No uncertainty is assigned for possible duality violations. The quoted experimental error in the table above corresponds to the statistical, experimental systematic and the b -> c l nu and b -> u l nu modeling errors. The other uncertainties contribute to the theoretical error.

It should be noted that the above results and averages do not include NNLO corrections. A paper By Neubert and collaborators (arxiv:0909.1609 [hep-ph]) suggests that these have non-negligible impact on the determination of Vub. Unfortunately, the numerical implementation of those corrections is not in a form that would be immediately suitable for public use by HFAG. Moreover, those results only include the NNLO corrections to the leading term in the 1/m_b expansion for the shape-function region. They neglect "kinematic" power corrections that become less and less suppressed as the phase space cuts are less restrictive. Therefore, while this subset of NNLO corrections are presumably dominant and important for restrictive cuts like P+<0.66 GeV cut, this should not be the case for less restrictive cuts like p* > 1.0 GeV. Therefore, we continue using the NLO code and we remark that for restrictive cuts one may expect that the NNLO corrections induce order 5.8 % upward shifts in Vub.

Determination of |Vub| (DGE)

The |Vub| values are obtained using the HQE input parameter:

obtained from the global fit in the kinetic scheme

|Vub| (DGE)
Experiment Value [10-3] Parameters References Remarks
CLEO (Ee) 3.90 ± 0.45 + 0.26 - 0.28 input Phys.Rev.Lett.88:231803,2002
[arXiv:hep-ex/0202019v1]
2.1 < Ee < 2.6
BELLE sim. ann. (mX, q2) 4.46 ± 0.47 + 0.20 - 0.22 input Phys.Rev.Lett.92:101801,2004
[arXiv:hep-ex/0311048v2]
Cut on mX<1.7 GeV, q2>8GeV2
tag with annealing method
BELLE (Ee) 4.85 ± 0.45 + 0.21 - 0.25 input Phys.Lett.B621:28-40 (2005)
[arXiv:hep-ex/0504046v2]
1.9 < Ee < 2.6
BABAR (Ee) 4.34 ± 0.25 + 0.23 - 0.25
input Phys.Rev.D73:012006,2006
[arXiv:hep-ex/0509040v2]
2.0 < Ee < 2.6
BABAR (Ee, shmax) 4.17 ± 0.20 + 0.28 - 0.29 input preliminary update (EPS2013) of
Ee > 2.0 shmax <3.5
BELLE multivariate (p*) 4.63 ± 0.28 + 0.13 - 0.13 input Phys.Rev.Lett.104:021801,2010
[arXiv:0907.0379v1 [hep-ex]]
BRECO tag; multivariate analysis.
Cut on lepton energy at 1 GeV
BABAR (mX<1.55) 4.53 ± 0.21 + 0.24 - 0.22 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX< 1.55 GeV
BABAR (mX<1.7) 4.26 ± 0.24 + 0.26 - 0.24 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX<1.7 GeV
BABAR (mX<1.7, q2>8) 4.27 ± 0.22 + 0.20 - 0.20 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at mX<1.7 GeV, q2>8 GeV2
BABAR (P+<0.66) 4.24 ± 0.26 + 0.37 - 0.32 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at P+<0.66 GeV
BABAR (mX, q2 fit, p*>1GeV) 4.46 ± 0.24 + 0.13 - 0.13 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit (mX, q2), cut at p*>1GeV
BABAR (p*>1.3GeV) 4.44 ± 0.27 + 0.15 - 0.14 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit p*, cut at p*>1.3GeV
Average ± exp + theory - theory 4.52 ±0.16 + 0.15 - 0.16 χ2/dof = 9.46/11
(CL = 0.58)
Plots: eps pdf gif mb input from global fit in the kinetic scheme

The full breakdown of the uncertainties on the average |Vub| above is (all errors quoted in percent):

positive errors: +1.8stat +1.7exp +1.3b2c model +2.1b2u model +0.5alpha_s R_CUT +3.2mb +0.0WA +0.5DGE theory =+4.8tot

negative errors: -1.8stat -1.7exp -1.3b2c model -1.9b2u model -0.5alpha_s R_CUT -3.0mb -1.9WA -0.3DGE theory =-5.0tot

where the fractions correspond to the statistical error (stat), the experimental systematics (exp), the modeling, e.g. branching fractions for exclusive decays, of the b -> c l nu and b -> u l nu decays (b2c model and b2u model, respectively), the effect of the alphas uncertainty on R_CUT (alpha_s R_CUT), the effect of the uncertainty on mb on the prediction of the event fraction and the total rate (mb), the Weak Annihilation (WA) and from the change and variation of scale of the matching scheme (DGE theory). The quoted experimental error in the table above corresponds to the statistical, experimental systematic and the b -> c l and b -> u l nu modeling errors. The other uncertainties contribute to the theoretical error.

Determination of |Vub| (GGOU)

The |Vub| values are obtained using the HQE input parameters:

obtained from the global fit in the kinetic scheme

The BABAR (Ee, shmax) analysis is not included in the average, since the Ee, shmax cuts are not yet implemented in the model.

|Vub| (GGOU)
Experiment Value [10-3] Parameters References Remarks
CLEO (Ee) 4.21 ± 0.49 +0.23 -0.33 input Phys.Rev.Lett.88:231803,2002
[arXiv:hep-ex/0202019v1]
2.1 < Ee < 2.6
BELLE sim. ann. (mX, q2) 4.50 ± 0.47 +0.28 -0.31 input Phys.Rev.Lett.92:101801,2004
[arXiv:hep-ex/0311048v2]
Cut on mX<1.7 GeV, q2>8GeV2
tag with annealing method
BELLE (Ee) 4.93 ± 0.46 +0.17 -0.22 input Phys.Lett.B621:28-40 (2005)
[arXiv:hep-ex/0504046v2]
1.9 < Ee < 2.6
BABAR (Ee) 4.50 ± 0.26 +0.18 -0.25 input Phys.Rev.D73:012006,2006
[arXiv:hep-ex/0509040v2]
2.0 < Ee < 2.6
BELLE multivariate (p*) 4.60 ± 0.27 + 0.10 - 0.11 input Phys.Rev.Lett.104:021801,2010
[arXiv:0907.0379v1 [hep-ex]]
BRECO tag; multivariate analysis.
Cut on lepton energy at 1 GeV
BABAR (mX<1.55) 4.29 ± 0.20 + 0.21 - 0.22 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX< 1.55 GeV
BABAR (mX<1.7) 4.09 ± 0.23 + 0.18 - 0.19 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX<1.7 GeV
BABAR (mX<1.7, q2>8) 4.32 ± 0.23 + 0.27 - 0.30 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at mX<1.7 GeV, q2>8 GeV2
BABAR (P+<0.66) 4.24 ± 0.26 + 0.32 - 0.32 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at P+<0.66 GeV
BABAR (mX, q2 fit, p*>1GeV) 4.42 ± 0.24 + 0.09 - 0.11 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit (mX, q2), cut at p*>1GeV
BABAR (p*>1.3GeV) 4.41 ± 0.27 + 0.10 - 0.12 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit p*, cut at p*>1.3GeV
Average ± exp + theory - theory 4.51 ± 0.16 + 0.12 - 0.15 χ2/dof = 8.80/10
(CL=0.55)
Plots: eps pdf gif mb input from global fit in the kinetic scheme

The full breakdown of the uncertainties on the average |Vub| above is (all errors quoted in percent):

positive errors: +1.9stat +1.7exp +1.3b2c model +1.9b2u model +1.6par. +1.5pert. +1.4q2* +0.0WA +0.2ff =+4.3tot

negative errors: -1.9stat -1.7exp -1.3b2c model -1.9b2u model -1.6par. -1.5pert. -1.4q2* -2.0WA -0.2ff =-4.8tot

where the fractions correspond to the statistical error (stat), the experimental systematics (exp), the modeling, e.g. branching fractions for exclusive decays, of the b -> c l nu and b -> u l nu decays (b2c model and b2u model, respectively), the value of alpha_s, mb and other non-perturbative parameters (par.), higher order perturbative and non-perturbative corrections (pert.), the modelling of the q2 tail and choice of the scale q2* (q2*), the WA matrix element (WA), the functional form of the distribution functions (ff).

Determination of |Vub| (ADFR)

The |Vub| values are obtained using the HQE input parameter:

obtained from the global fit in the kinetic scheme Also, the charm quark mass, to which the ADFR calculation is particularly sensitive, was fixed to the value quoted in arxiv:1102.2264 [hep-ph], mc (mc, MSbar) = 1.277 ± 0.026 GeV.

|Vub| (ADFR)
Experiment Value [10-3] Parameters References Remarks
CLEO (Ee) 3.44 ± 0.40 + 0.16 - 0.16 input Phys.Rev.Lett.88:231803,2002
[arXiv:hep-ex/0202019v1]
2.1 < Ee < 2.6
BELLE sim. ann. (mX, q2) 3.94 ± 0.41 + 0.17 - 0.17 input Phys.Rev.Lett.92:101801,2004
[arXiv:hep-ex/0311048v2]
Cut on mX<1.7 GeV, q2>8GeV2
tag with annealing method
BELLE (Ee) 4.50 ± 0.42 + 0.20 - 0.20 input Phys.Lett.B621:28-40 (2005)
[arXiv:hep-ex/0504046v2]
1.9 < Ee < 2.6
BABAR (Ee) 3.94 ± 0.22 + 0.20 - 0.19 input Phys.Rev.D73:012006,2006
[arXiv:hep-ex/0509040v2]
2.0 < Ee < 2.6
BABAR (Ee, shmax) 3.64 ± 0.18 + 0.17 - 0.17 input preliminary update (EPS2013) of
[arXiv:hep-ex/0506036v3]
Ee > 2, shmax < 3.5
BELLE multivariate (p*) 4.52 ± 0.30 + 0.19 - 0.19 input Phys.Rev.Lett.104:021801,2010
[arXiv:0907.0379v1 [hep-ex]]
BRECO tag; multivariate analysis.
Cut on lepton energy at 1 GeV
BABAR (mX<1.55) 3.84 ± 0.18 + 0.19 - 0.19 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX< 1.55 GeV
BABAR (mX<1.7) 3.76 ± 0.21 + 0.18 - 0.17 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut on hadronic mass mX<1.7 GeV
BABAR (mX<1.7,q2>8) 3.76 ± 0.20 + 0.17 - 0.16 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at mX<1.7 GeV, q2>8 GeV2
BABAR (P+<0.66) 3.59 ± 0.22 + 0.19 - 0.18 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Cut at P+<0.66 GeV
BABAR ((mX-q2) fit, p*>1) 4.35 ± 0.24 + 0.18 - 0.18 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit (mX, q2), cut at p*>1GeV
BABAR (p*>1.3) 4.30 ± 0.27 + 0.19 - 0.18 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
BRECO tag.
Fit p*, cut at p*>1.3GeV
Average ± exp + theory - theory 4.05 ± 0.13 + 0.18 - 0.11 χ2/dof = 31.9/11
(CL = 0.001)
Plots: eps pdf gif
The full breakdown of the uncertainties on the average |Vub| above is (all errors quoted in percent):

positive errors: +1.8stat +1.8exp +1.4b2c model +1.3b2u model +1.1alpha_s +2.0Vcb +0.7mb +0.4mc +0.8BF +3.5model =+5.4tot

negative errors: -1.8stat -2.0exp -1.4b2c model -1.3b2u model -1.0alpha_s -2.0Vcb -0.7mb -0.7mc -0.7BF -3.5model =-5.3tot

where the fractions correspond to the statistical error (stat), the experimental systematics (exp), the modeling, e.g. branching fractions for exclusive decays, of the b -> c l nu and b -> u l nu decays (b2c model and b2u model, respectively), the effect of the alphas uncertainty (alpha_s), the effect of the uncertainty on Vcb (Vcb), on the b-quark mass in the MS scheme (mb), on the c-quark mass in the MS scheme (mc), on the semileptonic BF (BF) and on the model (model). The quoted experimental error in the table above corresponds to the statistical, experimental systematic and the b -> c l and b -> u l nu modeling errors. The other uncertainties contribute to the theoretical error.

Determination of |Vub| (BLL) using the (mx-q2) analyses

The |Vub| values are obtained using the HQE input parameter:

obtained from a global fit in the 1S scheme

|Vub| (BLL) using the (mx-q2) analyses
Experiment Value [10-3] Parameters References Remarks
BELLE breco (mX, q2) 5.01 ± 0.39 ± 0.32 input Phys.Rev.Lett.95:241801,2005
[hep-ex/0505088]
mX-q2, BRECO tag
BELLE sim. ann. (mX, q2) 4.68 ± 0.49 ± 0.30 input Phys.Rev.Lett.92:101801,2004
[arXiv:hep-ex/0311048v2]
mX - Q2, tag with annealing method
BABAR (mX, q2) 4.50 ± 0.24 ± 0.29 input arxiv:1112.0702v1 submitted to PRD
[arXiv:1112.0702v1]
mX-q2, BRECO tag
Average ± exp ± theory 4.62 ± 0.20 ± 0.29 χ2/dof = 1.4/2
(CL = 0.50)
Plots: eps pdf gif HQE parameter input from b to c l nu and b to s gamma moments

The full breakdown of the uncertainties on the average |Vub| above is (all errors quoted in percent):

positive errors: +3.3stat +3.0exp +1.6b2c model +1.1b2u model +3.0Strf +3.0Pert +2.5Sf +4.0H.O. = +7.7tot

negative errors: -3.3stat -3.0exp -1.6b2c model -1.1b2u model -3.0Strf -3.0Pert -2.5Sf -4.0H.O. = -7.7tot

where the fractions correspond to the statistical error (stat), the experimental systematics (exp), the modeling, e.g. branching fractions for exclusive decays, of b -> c l nu and b -> u l nu decays (b2c model and b2u model, respectively), the residual shape function effects (Strf), the higher order terms in the alphas expansion (Pert), the uncertainty on the b-quark mass (Sf), and the third order terms in the OPE expansion(H.O.). No uncertainty is assigned for possible duality violations.

Shape Function Model Independent extraction of |Vub| from inclusive decays and comparison of results

Several years ago, M. Neubert (Phys. Rev. D49, 4623 (1994) ) suggested that |Vub| could be extracted by combining weighted integrals over the photon spectrum in B->Xs gamma decays with integrals over the lepton momentum spectrum near the kinematic endpoint in inclusive B->Xulnu decays decays. The underlying assumption is that the QCD interactions affecting these two processes are the same to leading order, and therefore ratios of decay rates for the two processes have significantly lower sensitivity to the choice of the shape-functions parameterization.
So far, there are two BABAR measurements based on this suggestion to extract |Vub| from charmless B-meson decays from inclusive distributions for different regions of phase space.
BABAR measured |Vub| in inclusive decays using the prescription of Leibovich, Low, and Rothstein (LLR), Phys.Rev.D62:014010,2000 [arXiv:hep-ph/0001028v2], and Phys.Lett.B486:86-91,2000 [arXiv:hep-ph/0005124v1], that extracts |Vub| with reduced model dependence by combining data of the hadronic mass spectrum from B->Xulnu decays with that of the photon energy spectrum from B->Xs gamma decays (Phys.Rev. D72 (2005) 052004 [arXiv:hep-ex/0508004v2]).
Using BABAR measurements of the lepton momentum spectrum near the kinematic endpoint, Phys.Rev. D73 (2006) 012006 [arXiv:hep-ex/0509040v2], two different theoretical prescriptions were tried to extract |Vub|, Phys.Rev.D76:114003,2007 [arXiv:hep-ph/0702072], namely LLR (Phys.Rev. D61 (2000) 053006 [arXiv:hep-ph/9909404v2]]) and LNP, a calculation by Lange, Neubert and Paz (JHEP 0510 (2005) 084 [arXiv:hep-ph/0508178v2] and JHEP 0601 (2006) 104 [arXiv:hep-ph/0511098v1]). In the following, we provide a comparison of the results of the different |Vub| extractions.

The errors on |Vub| are experimental and theoretical, respectively, for the first three results and experimental on B->Xulnu, experimental on B->Xsgamma, theoretical and due to |Vts| for the last two measurments.

Description Vub [10-3] Reference
HFAG Ave. (BLNP) 4.40 ± 0.15 +0.19 - 0.21
HFAG Ave. (DGE) 4.45 ± 0.15+ 0.15 - 0.16
HFAG Ave. (GGOU) 4.39 ± 0.15 + 0.12 - 0.20
HFAG Ave. (ADFR) 4.03 ± 0.13 + 0.18 - 0.12

HFAG Ave. (BLL) 4.62 ± 0.20 + 0.29 - 0.29
BABAR (LLR) 4.43 ± 0.45 ± 0.29 Phys.Rev.Lett. 96 (2006) 221801 [arXiv:hep-ex/0601046v2]
BABAR endpoint (LLR) 4.28 ± 0.29 ± 0.29 ± 0.26 ± 0.28 Phys.Rev.D76:114003,2007 [arXiv:hep-ph/0702072]
BABAR endpoint (LNP) 4.40 ± 0.30 ± 0.41 ± 0.23 Phys.Rev.D76:114003,2007 [arXiv:hep-ph/0702072]

A plot of this table is available in three formats: eps pdf gif

Inclusive Branching Fraction: B --> Xulnu (P*lep > 1.0 GeV/c)

We report the average for the branching fractions of B --> Xulnu with P*lep > 1.0 GeV/c.
Experiment BF [10-3] Parameters Remarks
BELLE Tagged 1.96 +/- 0.17+/- 0.16 input     parameters Phys.Rev.Lett.104, 021801 (2010) [arXiv:0907.0379 [hep-ex]]
BABAR Tagged 1.80 +/- 0.13+/- 0.15 input     parameters Submitted to PRD [arXiv:1112.0702 [hep-ex]]
Average 1.86 +/- 0.10 +/- 0.14 chi2/dof = 0.41/1 (CL = 52%) eps pdf gif

|Vub| from exclusive semileptonic B decays

Branching fractions of B0 -> pi- l+ nu

The measurements quoted here include both B0 and B+ decays. The average assumes equality of the semileptonic decays widths for these isospin-conjugate states, and is quoted for B0 decays.

Please note that the results of the untagged measurements by CLEO and BABAR are based on a combined analysis of B0 -> pi- l+ nu and B+ -> pi0 l+nu decays, assuming isospin symmetry.

Experiment / Mode BF [10-4] BF(q2<12 GeV2) [10-4] BF(q2<16 GeV2) [10-4] BF(q2>16 GeV2) [10-4] Reference
BABAR had. tag: B+ -> pi0 l+ nu × 2 τ0+ 1.52 +/- 0.41 +/- 0.30 0.67 +/- 0.30 +/- 0.12 1.04 +/- 0.35 +/- 0.18 0.48 +/- 0.22 +/- 0.12 Breco tag, Phys. Rev. Lett.97, 211801 (2006) [hep-ex/0607089] (input)(param)
Belle had. tag: B+ -> pi0 l+ nu × 2 τ0+ 1.48 +/- 0.15 +/- 0.08 0.78 +/- 0.11 +/- 0.04 1.09 +/- 0.12 +/- 0.06 0.36 +/- 0.07 +/- 0.02 Breco tag, Phys. Rev. D88, 032005 (2013) [arXiv:1306.2781 [hep-ex]] (input)(param)
BABAR sl. tag: B+ -> pi0 l+ nu × 2 τ0+ 1.78 +/- 0.28 +/- 0.15 1.07 +/- 0.20 +/- 0.09 1.35 +/- 0.22 +/- 0.11 0.44 +/- 0.17 +/- 0.06 SL tag, Phys. Rev. Lett 101, 081801 (2008) [arXiv:0805.2408] (input)(param)
Belle sl. tag: B+ -> pi0 l+ nu × 2 τ0+ 1.41 +/- 0.26 +/- 0.15 0.71 +/- 0.17 +/- 0.08 1.05 +/- 0.22 +/- 0.12 0.37 +/- 0.15 +/- 0.04 SL tag, Phys. Lett. B648, 139-148 (2007) [hep-ex/0604024] (input)(param)
BABAR had. tag: B0 -> pi- l+ nu 1.07 +/- 0.27 +/- 0.19 0.26 +/- 0.15 +/- 0.04 0.42 +/- 0.18 +/- 0.06 0.65 +/- 0.20 +/- 0.13 Breco tag, Phys. Rev. Lett.97, 211801 (2006) [hep-ex/0607089] (input)(param)
Belle had. tag: B0 -> pi- l+ nu 1.49 +/- 0.09 +/- 0.07 0.81 +/- 0.06 +/- 0.04 1.06 +/- 0.07 +/- 0.05 0.45 +/- 0.05 +/- 0.02 Breco tag, Phys. Rev. D88, 032005 (2013) [arXiv:1306.2781 [hep-ex]] (input)(param)
BABAR sl. tag: B0 -> pi- l+ nu 1.38 +/- 0.21 +/- 0.08 0.77 +/- 0.14 +/- 0.05 0.92 +/- 0.16 +/- 0.05 0.46 +/- 0.13 +/- 0.03 SL tag, Phys. Rev. Lett 101, 081801 (2008) [arXiv:0805.2408] (input)(param)
Belle sl. tag: B0 -> pi- l+ nu 1.41 +/- 0.19 +/- 0.15 0.80 +/- 0.14 +/- 0.08 1.04 +/- 0.16 +/- 0.11 0.37 +/- 0.10 +/- 0.04 SL tag, Phys. Lett. B648, 139-148 (2007) [hep-ex/0604024] (input)(param)
CLEO untagged: B -> pi l nu 1.38 +/- 0.15 +/- 0.11 0.69 +/- 0.12 +/- 0.07 0.97 +/- 0.13 +/- 0.09 0.41 +/- 0.08 +/- 0.04 Untagged, Phys. Rev. Lett.99, 041802 (2007) [arXiv:hep-ex/0703041v2] (input)(param)
BABAR untagged (6 q2 bins): B -> pi l nu 1.41 +/- 0.05 +/- 0.08 0.88 +/- 0.04 +/- 0.05 1.10 +/- 0.04 +/- 0.06 0.32 +/- 0.02 +/- 0.03 Untagged, Phys. Rev. D83, 032007 (2011) [arXiv:1005.3288v2 [hep/ex] ] (input)(param)
BABAR untagged (12 q2 bins): B -> pi l nu 1.44 +/- 0.04 +/- 0.06 0.83 +/- 0.03 +/- 0.04 1.08 +/- 0.04 +/- 0.05 0.37 +/- 0.02 +/- 0.02 Untagged loose neutrino, Phys. Rev. D86, 092004 (2012) [arXiv:1201.1253 [hep/ex] ] (input)(param)
Belle untagged: B0 -> pi- l+ nu 1.48 +/- 0.04 +/- 0.07 0.82 +/- 0.03 +/- 0.04 1.09 +/- 0.03 +/- 0.05 0.40 +/- 0.02 +/- 0.02 Untagged, Phys. Rev. D83, 071101 (2011) [arXiv:1012.0090 [hep-ex]] (input)(param)
Average: B0 -> pi- l+ nu 1.45 +/- 0.02 +/- 0.04 0.81 +/- 0.02 +/- 0.02 1.06 +/- 0.02 +/- 0.03 0.38 +/- 0.01 +/- 0.01 Plots: eps pdf gif   chi2/dof = 3.4/11 (CL = 0.98)

Exclusive |Vub| determination

The partial BFs quoted above along with theoretical calculations of the form factor normalization can be used to determine |Vub|. The |Vub| results obtained from the HFAG averages for the partial BFs combined with different form factor calculations are shown below. Note that the FNAL/MILC and HPQCD unquenched LQCD calculations are not entirely independent. We also do not use their quenched results as they are superseded by the unquenched results. The calculations by Ball-Zwicky and Khodjamirian et al. are based on light-cone sum rules.  At this time we do not attempt to average the |Vub| results obtained with different calculations or select a best value.

The errors on |Vub| are experimental and theoretical.

FF calculation q2 range FF norm. (ps-1) |Vub| [10-3] Reference
Khodjamirian et al. <12 GeV2 4.59 +1.00 -0.85 3.41 +/- 0.06 +0.37-0.32 Phys. Rev. D83:094031 (2011) [arXiv:1103.2655 [hep/ph]]
Ball-Zwicky <16 GeV2 5.44 +/- 1.43 3.58 +/- 0.06 +0.59-0.40 Phys. Rev. D71:014015 (2005) [hep-ph/0406232]
HPQCD >16 GeV2 2.02 +/- 0.55 3.52 +/- 0.08 +0.61-0.40 Phys.Rev. D73, 074502 (2006), Erratum-ibid.D75:119906,2007 [hep-lat/0601021]
FNAL/MILC >16 GeV2 2.21 +0.47 -0.42 3.36 +/- 0.08 +0.37-0.31 Phys. Rev. D79, 054507 (2009) [arXiv:0811.3640v3 [hep-lat]]

A plot of this table is available in three formats: eps pdf gif

Consistent results are obtained using quenched Lattice QCD calculations (eg. arXiv:hep-lat/0011065).

|Vub| can also be determined from a simultaneous fit of a B -> pi form factor parameterization to data and LQCD calculations. In contrast to the |Vub| determinations presented above, this fit makes use of the measured q2 spectra over the full q2 range. We choose the BCL parameterization (Bourrely, Caprini and Lellouch, Phys. Rev. D79, 013008 (2009) [arXiv:0807.2722v3 [hep-ph]]. A fit of the BCL parameterization with 3+1 parameters (3 parameters for the BCL parameterization: b0,b1,b2 and one parameter for |Vub| to be determined from the relative normalization of data and LQCD results) to the four most precise measurements of BABAR and Belle (BABAR untagged 6 q2 bins B0+B+, BABAR untagged 12 q2 bins B0+B+, Belle untagged B0, Belle had. tag B0) and the FNAL/MILC lattice predictions yields the following results:

|Vub| = (3.28 +- 0.29) × 10-3
b1/b0 = -1.02 +- 0.18
b2/b0 = -1.20 +- 0.57

For the product f+(0)|Vub| we obtain: f+(0)|Vub| = (0.923 +- 0.024) × 10-3.

The quoted errors are the combined experimental and theoretical errors obtained from the fit. The probability of the fit is 0.053 (χ2/dof = 60.2/44).
Only 4 of the 12 LCQD points were used to avoid the high correlations between neighboring points.

A plot of the fit result is available in three formats: eps pdf gif

The simultaneous fit to data and theory has also been performed with the most recent light-cone sum rule result for f+(0) (f+(0) = 0.261 +0.020-0.023 from A. Bharucha, JHEP 1205 (2012) 092 [arXiv:1203.1359 [hep-ph]]), i.e. a single theory point at q2 = 0 GeV2 is used instead of the FNAL/MILC results at high q2. This fit gives consistent results:

|Vub| = (3.53 +- 0.29) × 10-3
b1/b0 = -0.99 +- 0.20
b2/b0 = -1.28 +- 0.61
f+(0)|Vub| = (0.922 +- 0.024) × 10-3
Probability: 0.029 (χ2/dof = 59.8/41)

A plot of the fit result is available in three formats: eps pdf gif

Branching fractions of B0 -> rho- l+nu

The measurements quoted here include both B0 and B+ decays; the average assumes equality of the semileptonic decays widths for these isospin-conjugate states, and is quoted for B0 decays.

Experiment/Mode BF [10-4] Reference
CLEO untagged: B^{0} - > \rho^{-} l^{+} \nu 2.75 +/-0.41 +/- 0.52 Phys.Rev.D61, 052001 (2000) [hep-ex/9905056] (input)
CLEO untagged: B^{0} -> \rho^{-} l^{+} \nu 2.93 +/-0.37 +/- 0.37 Phys.Rev.Lett.99, 041802 (2007)[arXiv:hep-ex/0703041v2] (input)
BELLE sl.tag: B^{0} -> \rho^{-} l^{+} \nu 2.17 +/-0.54 +/-0.32 Phys.Lett.B648:139-148,2007 [hep-ex/0604024] (input) (param)
BELLE sl.tag: B^{+} -> \rho^{0} l^{+} \nu 2.47 +/-0.43 +/-0.33 Phys.Lett.B648:139-148,2007 [hep-ex/0604024] (input) (param)
BABAR untagged: B^{0} -> \rho^{-} l^{+} \nu 1.98 +/-0.21 +/-0.38 Phys.Rev.D72, 051102 (2011) [arXiv:1005.3288] (input) (param)
BABAR untagged: B^{+} -> \rho^{0} l^{+} \nu 1.87 +/-0.19 +/-0.32 Phys.Rev.D72, 051102 (2011) [arXiv:1005.3288] (input) (param)
BELLE had.tag: B^{0} -> \rho^{-} l^{+} \nu 3.22 +/-0.27 +/-0.24 Phys.Rev.D 88, 032005 (2013)[arXiv:hep-ex/0703041v2] (input)(param)
BELLE had.tag: B^{+} -> \rho^{0} l^{+} \nu 3.39 +/-0.18 +/-0.18 Phys.Rev.D 88, 032005 (2013)[arXiv:hep-ex/0703041v2] (input)(param)
Average: B ^{0} -> \rho^{-} l^{+} \nu 2.94 +/- 0.11 +/- 0.17 Plots: eps pdf gif   chi2/dof = 12.8/7 (CL = 0.08)

Exclusive Branching Fraction: B- -> Omega l nu

Experiment/Mode BF [10-4] Parameters Reference
BELLE untag 1.30 +/- 0.40 +/- 0.36 input     parameters Phys.Rev.Lett 93, 131803 (2004) [arXiv:0402023 [hep-ex]]
BABAR untag (loose nu-reco) 1.19 +/- 0.16 +/- 0.09 input     parameters Phys.Rev.D 86, 092004 (2012) [arXiv:1208.1253 [hep-ex]]
BABAR untag 1.21 +/- 0.14 +/- 0.08 input     parameters Phys.Rev.D87, 032004 (2013) [arXiv:1205.6245 [hep-ex]]
BELLE had.tag 1.07 +/- 0.16 +/- 0.07 input     parameters Phys.Rev.D 88, 032005 (2013) [arXiv:1306.2781 [hep-ex]]
BABAR sl.tag 1.35 +/- 0.21 +/- 0.11 input     parameters Phys.Rev.D88, 072006 (2013) [arXiv:1308.2589 [hep-ex]]
Average 1.191+/- 0.084 +/- 0.055 chi2/dof = 0.02 (CL = 0.91) eps pdf gif

Exclusive Branching Fraction: B- -> eta l nu

Experiment/Mode BF [10-4] Parameters Reference
BABAR untagged 0.31+/- 0.06+/- 0.08 input     parameters Phys.Rev.D79, 052011 (2008) [arXiv:0808.3524 [hep-ex]]
BABAR sl.Tag 0.64+/- 0.20+/- 0.03 input     parameters Phys.Rev.Lett 101, 081801 (2008) [arXiv:0805.2408 [hep-ex]]
CLEO 0.44+/- 0.23+/- 0.11 (<1.01 at 90% C.L.) input     parameters Phys.Rev.D76, 012007 (2007) [arXiv:0703041[hep-ex]]
BABAR untagged (loose nu-reco) 0.36+/- 0.05+/- 0.04 input     parameters Phys.Rev.D83, 052011 (2011) [arXiv:1010.0987 [hep-ex]]
Average 0.37 +/- 0.04 +/- 0.04 chi2/dof = 2.3/3. (CL = 0.51) eps pdf gif

Exclusive Branching Fraction: B- -> eta' l nu

Experiment/Mode BF [10-4] Parameters Reference
CLEO untagged 2.71+/- 0.80+/- 0.56 input     parameters Phys.Rev.D76, 012007 (2007) [arXiv:0703042[hep-ex]]
BABAR sl.tag 0.04+/- 0.22+/- 0.04 (<0.47 at 90% C.L.) input     parameters Phys.Rev.Lett 101, 081801 (2008) [arXiv:0808.3524 [hep-ex]]
BABAR untagged (loose nu-reco) 0.24 +/- 0.08 +/- 0.03 input     parameters Phys.Rev.D83, 052011 (2011) [arXiv:1010.0987 [hep-ex]]
Average 0.23 +/- 0.08 +/- 0.03 chi2/dof = 7.2/2. (CL = 0.03) eps pdf gif


Last update: Oct 10, 2014