Updates of Semileptonic Results for Summer 2006

This web edition is complemented by the 2006 HFAG summary of averages (arXiv:0704.3575v1 [hep-ex]).
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Exclusive Branching Fraction: B0 -> Dlnu

This is a one-dimensional fit for the average branching fraction.
Experiment BF (rescaled) [%] Parameters Remarks
ALEPH 2.15 +/- 0.18+/- 0.37 input     parameters Phys.Lett.B395:373-387,1997 [Spires]
CLEO 2.07+/- 0.13+/- 0.16 input     parameters Phys.Rev.Lett.82:3746,1999 [hep-ex/9811042]
BELLE 2.13+/- 0.12+/- 0.39 input     parameters Phys.Lett.B526:258-268,2002 [hep-ex/0111082]
Average 2.09+/- 0.18 chi2/dof = 0.04/2 (CL = 0.98) eps pdf gif
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Exclusive Branching Fraction: B0 -> D*lnu

This is a one-dimensional fit for the average branching fraction.
Experiment BF (rescaled) [%] Parameters Remarks
ALEPH (excl) 5.72 +/- 0.27 +/- 0.35 input     parameters Phys.Lett.B395:373-387,1997 [Spires]
OPAL (excl) 5.24 +/- 0.20 +/- 0.37 input     parameters Exclusive reco, Phys.Lett.B482:15-30,2000 [hep-ex/0003013]
OPAL (partial reco) 6.17 +/- 0.28 +/- 0.58 input     parameters Partial reco, Phys.Lett.B482:15-30,2000 [hep-ex/0003013]
DELPHI (partial reco) 5.00 +/- 0.14 +/- 0.36 input     parameters Partial reco, Phys.Lett.B510:55-74,2001 [hep-ex/0104026]
BELLE (excl) 4.73 +/- 0.24 +/- 0.41 input     parameters Phys.Lett.B526:247-257,2002 [hep-ex/0111060]
CLEO (excl) 6.26 +/- 0.19 +/- 0.38 input     parameters Phys.Rev.Lett.89:081803,2002[hep-ex/0203032]
DELPHI (excl) 5.44 +/- 0.20 +/- 0.43 input     parameters Eur.Phys.J.C33:213,2004 [hep-ex/0401023]
BABAR (excl) 4.77 +/- 0.07 +/- 0.33 input     parameters Phys.Rev.D71:051502,2004 [hep-ex/0408027]
Average 5.28 +/- 0.18 chi2/dof = 13/7 (CL = 0.068) eps pdf gif

Exclusive |Vcb| F(1)

All the measurements in the following average had been recalibrated such that R_1=(1.417+/-0.061+/-0.044) and R_2=(0.836+/-0.037+/-0.022) is assumed, as measured by the BABAR collaboration (hep-ex/0607076).

This table and the plots in the last row document the two-dimensional simultaneous fit to |Vcb|*F(1) and rho2.
Experiment |Vcb| F(1) (rescaled) [10-3] rho2 (rescaled) Correlation (stat/syst/total) Parameters Remarks
ALEPH (excl) 32.8 +/- 1.8 +/- 1.3 0.57+/-0.25+/-0.12 0.94/0.60/0.72 input     parameters Phys.Lett.B395:373-,1997
OPAL (excl) 37.2 +/- 1.6 +/- 1.5 1.28+/-0.21+/-0.15 0.95/0.42/0.61 input     parameters Phys.Lett.B482:15-,2000
OPAL (partial reco) 37.9 +/- 1.2 +/- 2.4 1.15+/-0.14+/-0.30 0.77/0.70/0.71 input     parameters Phys.Lett.B482:15-,2000
DELPHI (partial reco) 36.2 +/- 1.4 +/- 2.3 1.36+/-0.14+/-0.27 0.94/0.77/0.79 input     parameters Phys.Lett.B510:55-,2001
BELLE (excl) 35.2 +/- 1.9 +/- 1.7 1.31+/-0.16+/-0.11 0.91/0.68/0.78 input     parameters Phys.Lett.B526:247-,2002
CLEO (excl) 42.7 +/- 1.3 +/- 1.6 1.47+/-0.09+/-0.09 0.87/0.62/0.67 input     parameters Phys.Rev.Lett.89:081803,2002
DELPHI (excl) 37.1 +/- 1.8 +/- 1.9 1.13+/-0.15+/-0.16 0.89/0.50/0.58 input     parameters Eur.Phys.J.C33:213,2004
BABAR (excl) 34.7 +/- 0.3 +/- 1.1 1.18+/-0.05+/-0.03 0.27 input     parameters Preliminary hep-ex/0607076 & Phys.Rev.D74:092004,2006 (supersedes Phys.Rev.D71:051502,2004)
Average 36.0 +/- 0.6 1.19 +/- 0.05 0.69/0.40/0.46 chi2/dof = 31.1/14 (CL = 0.0054) eps 1  pdf 1  gif 1  eps 2  pdf 2  gif 2 
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Exclusive |Vcb|G(1)

This table and the plots in the last row document the two-dimensional simultaneous fit to |Vcb|*G(1) and rho2. Note: The fit is two-dimensional, no confidence level is given at the moment.
Experiment |Vcb| G(1) (rescaled) [10-3] rho2 (rescaled) Correlation (stat/syst/total) Parameters Remarks
ALEPH 39.03+/- 11.80+/- 6.20 0.96+/- 0.98+/- 0.36 0.98/0.99/0.96 input     parameters Phys.Lett.B395:373-,1997
CLEO 44.84 +/- 5.90+/- 3.45 1.27+/- 0.25+/- 0.14 0.95/0.98/0.96 input     parameters Phys.Rev.Lett.82:3746-,1999
BELLE 41.11+/- 4.40 +/- 5.15 1.12+/- 0.22+/- 0.14 0.96/0.96/0.92 input     parameters Phys.Lett.B526:258-268,2002
Average 42.4+/- 4.5 1.17+/- 0.18 0.95/0.94/0.93 chi2/dof = 0.3/4 eps 1  pdf 1  gif 1  eps 2  pdf 2  gif 2 

Inclusive Semileptonic (Partial) Branching Fraction for B+/B0 Admixture: B -> Xlnu

This is a one-dimensional fit for the average partial branching fraction for a cut on the momentum
of the lepton at p* > 0.6 GeV/c as measured in the Upsilon(4S) frame.  Note for the Belle(Breco)
measurement, the cut was placed in the rest frame of the B-meson - the difference between the partial branching
above 0.6 GeV/c as measured in either the Upsilon(4S) and B-meson rest frames is entirely negligible.

Experiment BF (Rescaled) [%] Input Remarks
p(l) > 0.6 GeV/c
ARGUS (e tag) 9.17 +/- 0.50 +/- 0.33 input     parameters Phys.Lett.B318:397-404, 1993 [Spires]
BELLE (l tag) 10.32 +/- 0.11 +/- 0.46 input     parameters Phys.Lett.B547:181-192, 2002 [hep-ex/0208033]
CLEO (e tag) 10.24 +/- 0.08 +/- 0.22 input     parameters Phys.Rev.D70:032003,2004 [hep-ex/0403053]
BABAR (e tag) 10.37 +/- 0.06 +/- 0.23 input     parameters Phys.Rev.D69:111104, 2004 [hep-ex/0403030]
BABAR (B_{reco} tag) 10.03 +/- 0.19 +/- 0.33 input     parameters Phys.Rev.D74:091105,2006 [hep-ex/0607111]
BELLE (B_{reco} tag) 10.28 +/- 0.18 +/- 0.24 input     parameters Phys.Rev.D75:032001,2007 [hep-ex/0610012]
Average 10.24 +/- 0.15 chi2/dof = 4/5 (CL = 0.52) eps pdf gif
  
Using the results of a global fit (Phys.Rev.D73,073008(2006))
for HQET parameters in the Kinetic Scheme (Eur. Phys. J C 34 (2004) 181)
where none of the measurements listed above have been used as input, one can extract the extrapolation factor necessary to calculate the full branching fraction,  f_c = 1.0495 +/- 0.0005 +/- 0.0010, where the first error is from experiment and theory in the global fit and the second error is assigned as an additional theoretical uncertainty for the ratio Gamma_sl(0.6)/Gamma_sl(0.0) - for Gamma_sl total width this uncertainty is typically 1.5%, on the recommendation of the authors of the fit, for the ratio it is estimated to be 0.1%.
The full branching fraction is extracted as BF( B+/B0 -> X l nu ) = (10.75 +/- 0.16)% .

Inclusive Semileptonic Branching Fraction for B+ -> Xl+nu

  
Experiment BF (Rescaled) [%] Input Remarks
CLEO (l tag) 10.25 +/- 0.57 +/- 0.66 input     parameters Phys.Lett.B399:321,1997 [hep-ex/9702007]
BABAR (B_{reco} tag) 10.90 +/- 0.27 +/- 0.39 input     parameters Phys.Rev.D74:091105,2006 [hep-ex/0607111]
BELLE (B_{reco} tag) 11.17 +/- 0.25 +/- 0.28 input     parameters Phys.Rev.D75:032001,2007 [hep-ex/0610012]
Average 10.99 +/- 0.28 chi2/dof = 1/2 (CL = 0.61) eps pdf gif
  

Inclusive Semileptonic Branching Fraction for B0 -> X-l+nu

  
Experiment BF(B+->) (Rescaled) [%] Input Remarks
CLEO (partial tag) 9.9 +/- 3.0 +/- 0.9 input     parameters Phys.Rev.D45:2212-2231,1992 [Spires]
ARGUS (partial tag) 9.3 +/- 1.1 +/- 1.5 input     parameters Phys.Lett.B324:249-254,1994 [Spires]
CLEO (partial tag) 10.78 +/- 0.60 +/- 0.69 input     parameters Phys.Lett.B399:321-328,1997 [hep-ex/9702007]
BABAR (B_{reco} tag) 10.14 +/- 0.28 +/- 0.33 input     parameters Phys.Rev.D74:091105,2006 [hep-ex/0607111]
BELLE (B_{reco} tag) 10.46 +/- 0.30 +/- 0.23 input     parameters Phys.Rev.D75:032001,2007 [hep-ex/0610012]
Average 10.33 +/- 0.28 chi2/dof = 0.9/4 (CL = 0.92) eps pdf gif
  

Ratio of Semileptonic Branching Fractions for B+ to B0 -> X-l+nu

The total width of semileptonic B meson decays is expected to be the same for both neutral and charged mesons. Therefore the ratio of the branching fractions R+0 should be equivalent to the ratio of the B-meson lifetime Tau_B+/Tau_B0. Recently both Babar and Belle reported precise measurements of R_+0 for which we provide an average.   
Experiment R+/0(Rescaled) [%] Input Remarks
BABAR 1.084 +/- 0.041 +/- 0.025 input     Phys.Rev.D74:091105,2006 [hep-ex/0607111]
BELLE 1.069 +/- 0.040 +/- 0.026 input     Phys.Rev.D75:032001,2007 [hep-ex/0610012]
Average 1.076 +/- 0.034 chi2/dof = 0.05/1 (CL = 0.82) eps pdf gif
  

Inclusive Vub average for winter 2006

|Vub| in inclusive semileptonic B decays

The results in this section are determined by comparing the measured partial branching fractions to theoretical calculations of the corresponding rates, which are proportional to |Vub|2. We extract |Vub| using three theoretical frameworks:

The latter, BLL, although having been around for quite some time, has been added to our list of phenomenological frameworks from which one extract a value of |Vub|. BLL is a local OPE based approach that first advocated the use of a mX- q2 cut, to not only reduce large b->clnu background, but to reduce theoretical errors associated with the b-quark light cone distribution function or shape function, as it more widely known. The extraction is applied to results of  the partial branching fraction of inclusive charmless semileptonic B decays in the phase space  pl>1 GeV/c, mX < 1.7 GeV/c2 & q2 > 8 GeV2/c2.

We perform a total of five averages for the inclusive V_ub:

  1. BLNP using all the experimental measurements and only the mx-q2 ones
  2. DGE using all the experimental measurements and only the mx-q2 ones
  3. BLL using only the mx-q2 measurements

No attempt is made to average BLNP, DGE or BLL derived |Vub|.

For consistency among all the averages, we use the input parameters from the same global fit to data of B->Xc l nu  and B->Xs g decays using the latest measurements from the Collaborations: Eur. Phys. J C 34 (2004) 181. The global fit is performed in the Kinetic Scheme (Eur. Phys. J C 34 (2004) 181) and then the HQ parameters are translated to the other schemes. A global fit in the 1S scheme is currently under way. Earlier results can be found in Phys. Rev. D 70:094017 (2004).

The procedure for performing the average is documented in a brief note on averaging

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 negligible statistical correlations.

The errors in the tables are experimental (statistical and systematic) and external (theoretical and HQ parameter uncertainties). The average B lifetime used is 1.584 ps.

BLNP : Vub with HQ parameters from b -> c l nu and b -> s g moments

BLNP : |Vub| with HQ parameters from b -> c l nu and b -> s g moments

V_ub values are obtained using the HQ input parameters (from Phys.Rev.D73,073008(2006)):

with correlation coefficient -0.26 . 

BLNP Vub (B->Xc l nu & B->Xs g moments)
Experiment Value [10-3] Parameters References Remarks
CLEO (E_{e}) 4.09 +/- 0.48 +/- 0.37 input Phys.Rev.Lett.88:231803,2002 (hep-ex/0202019) 2.1 < p < 2.6, Vub redetermined from partial BF
BELLE sim. ann. (m_{X}, q^{2}) 4.37 +/- 0.46 +/- 0.29 input Phys.Rev.Lett.92:101801,2004 (hep-ex/0311048) mX - Q2, tag with annealing method
BELLE (E_{e}) 4.82 +/- 0.45 +/- 0.30 input Phys.Lett.B621:28-40 (2005) (hep-ex/0504046) 1.9 < p < 2.6
BABAR (E_{e}) 4.39 +/- 0.25 +/- 0.32 input Phys.Rev.D73:012006,2006 (hep-ex/0509040) 2.0 < p < 2.6, Vub redetermined from partial BF
BABAR (E_{e}, s^{max}_{h}) 4.57 +/- 0.31 +/- 0.42 input Phys.Rev.Lett.95:111801,2005 , Erratum-ibid.97:019903,2006 (hep-ex/0506036 (version 3, June 2006)) (Ee-q2)
BELLE m_{X} 4.06 +/- 0.27 +/- 0.24 input Phys.Rev.Lett.95:241801,2005 (hep-ex/0505088) mX, BRECO tag; other methods (mX-q2 and P not used)
BABAR (m_{X}, q^{2}) 4.75 +/- 0.35 +/- 0.31 input preliminary (hep-ex/0507017) mX-q2, BRECO tag
Average +/- exp +/- (mb,theory) 4.52 +/- 0.19 +/- 0.27 chi2/dof = 6.2/6 (CL = 0.41) Plots: eps pdf gif HQ 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):

+-2.1stat +-2.7exp +-2.1b2c model +-1.4b2u model +-4.1HQ param +-0.9sub SF +-3.8matching +-2.1WA = +-7.4tot

where the errors correspond to statistics, experimental systematics, the modeling of b -> c l nu and b -> u l nu decays, the HQ parameters mb and mupi2, subleading shape functions, variation of matching scales, and Weak Annihilation. No uncertainty is assigned for possible duality violations.

Using the average |Vub| along with the calculated full b -> u l nu rate from BLNP \(70.8/ps-1/|Vub|2) results in a total BF

BF(b -> u l nu) = (2.29 +- 0.34)*10-3

DGE : Vub with HQ parameters from b -> c l nu and b -> s g moments

DGE: |Vub| with b-quark mass from b -> c l nu and b -> s g moments

V_ub values are obtained using the HQ input parameter (from Phys.Rev.D73,073008(2006)):

DGE Vub (B->Xc l nu & B->Xs g moments)
Experiment Value [10-3] Parameters References Remarks
CLEO (E_{e}) 3.85 +/- 0.45 +/- 0.22 input Phys.Rev.Lett.88:231803,2002 (hep-ex/0202019) 2.1 < p < 2.6, Vub redetermined from partial BF
BELLE sim. ann. (m_{X}, q^{2}) 4.42 +/- 0.47 +/- 0.19 input Phys.Rev.Lett.92:101801,2004 (hep-ex/0311048) mX - Q2, tag with annealing method
BELLE (E_{e}) 4.80 +/- 0.45 +/- 0.20 input Phys.Lett.B621:28-40 (2005) (hep-ex/0504046) 1.9 < p < 2.6
BABAR (E_{e}) 4.29 +/- 0.29 +/- 0.21 input Phys.Rev.D73:012006,2006 (hep-ex/0509040) 2.0 < p < 2.6, Vub redetermined from partial BF
BABAR (E_{e}, s^{max}_{h}) 4.42 +/- 0.30 +/- 0.24 input Phys.Rev.Lett.95:241801,2005 (hep-ex/0506036 (version 3, June 2006)) (Ee-q2)
BELLE m_{X} 4.29 +/- 0.28 +/- 0.22 input Phys.Rev.Lett.95:241801,2005 (hep-ex/0505088) mX, BRECO tag; other methods (mX-q2 and P not used)
BABAR (m_{X}, q^{2}) 4.80 +/- 0.35 +/- 0.21 input preliminary (hep-ex/0507017) mX-q2, BRECO tag
Average +/- exp +/- (mb,theory) 4.46 +/- 0.20 +/- 0.20 chi2/dof = 10.0/6 (CL = 0.124) Plots: eps pdf gif m_b 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):

+-1.8stat +-2.5exp +-2.3b2c model +-2.3b2u model +-1.2mb (R_CUT) +-1.0alpha_s (R_CUT) +-3.0 (TOTAL SL WIDTH) +-2.9DGE theory

=+-6.3tot

where the errors correspond to statistics, experimental systematics, the modeling of b -> c l nu and b -> u l nu decays, effect of uncertainty on mb
on the prediction of  the event fraction (R_CUT),  effect  of alpha_s uncertainty on R_CUT, uncertainty on total semileptonic B width, and from the change
and variation of scale of the matching scheme (DGE theory).

Using the average |Vub| along with the calculated full b -> u l nu rate from DGE \(66.5/ps-1/|Vub|2) results in a total BF

BF(b -> u l nu) = (2.10 +- 0.29)*10-3

Vub comparison

Inclusive Vub comparison

The errors on |Vub| are experimental and theoretical, respectively.  Theoretical error uncertainties cannot be easily compared, but we have presented a breakdown on the main components for each calculation in the sections above.

Vub (B->Xc l nu & B->Xs g moments)
Theory framework Vub [10-3]
BLNP (Phys. Rev. D72:073006 (2005)) 4.52 +/- 0.19 +/- 0.27
DGE (JHEP 0601:097 (2006)) 4.46 +/- 0.20 +/- 0.20

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

BLL : Vub with HQ parameters from b -> c l nu and b -> s g moments (mx-q2)

BLL : |Vub| with HQ parameters from b -> c l nu and b -> s g moments (mx-q2)

V_ub values are obtained using the b-quark mass (from Phys.Rev.D73,073008(2006)) translated to the 1S scheme using hep-ph/0304132:

BLL Vub (B->Xc l nu & B->Xs g moments)
Experiment Value [10-3] Parameters References Remarks
BELLE breco (m_{X}, q^{2}) 5.04 +/- 0.39 +/- 0.37 input Phys.Rev.Lett.95:241801,2005 (hep-ex/0505088) mX-q2, BRECO tag
BELLE sim. ann. (m_{X}, q^{2}) 4.72 +/- 0.50 +/- 0.35 input Phys.Rev.Lett.92:101801,2004 (hep-ex/0311048) mX - Q2, tag with annealing method
BABAR (m_{X}, q^{2}) 5.12 +/- 0.38 +/- 0.38 input preliminary (hep-ex/0507017) mX-q2, BRECO tag
Average +/- exp +/- (mb,theory) 5.02 +/- 0.26 +/- 0.37 chi2/dof = 0.52/2 (CL = 0.77) Plots: gif  eps pdf HQ 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):

+-3.2stat +-2.9exp +-1.8b2c model +-2.4b2u model +-3.0Strf +-3.0Pert +-4.5Sf +-4.0H.O. = +-9.1tot

where the errors correspond to statistics, experimental systematics, the modeling of b -> c l nu and b -> u l nu decays, residual shape function effects (Strf), higher order terms in the $\alpha_s$ expansion (Pert), the uncertainty on the b-quark mass (Sf), and third order terms in the OPE expansion(H.O.). No uncertainty is assigned for possible duality violations. Comparison of Inclusive Vub using only mX-q2 measurements

Comparison of Inclusive Vub using only mX-q2 measurements

Here we provide a comparison of BLNP, DGE and BLL extracted from a common set of measurements made in the phase space pl>1 GeV/c, mX < 1.7 GeV/c2 & q2 > 8 GeV2/c2. The errors on |Vub| are experimental and theoretical, respectively. Theoretical error uncertainties cannot be easily compared, but we have presented a breakdown on the main components for each calculation in the sections above.

Vub (B->Xc l nu & B->Xs g moments)
Theory framework Vub [10-3]
HFAG Ave. (BLNP) mx-q2 (CL=0.79) 4.65 +/- 0.25 +/- 0.31
HFAG Ave. (DGE) mx-q2 (CL=0.77) 4.70 +/- 0.26 +/- 0.22
HFAG Ave. (BLL) mx-q2 (CL=0.77) 5.02 +/- 0.26 +/- 0.37

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

Vub comparison_with LLR method

Shape Function Model Independent extraction of Inclusive Vub comparison

Above we have used two theoretical formulations to extract|Vub|from measurements of inclusive charmless B-meson decays in various kinematic regions of phase space. Recently BABAR measured inclusive |Vub|using the prescription of Leibovich, Low, and Rothstein (LLR), Phys.Rev.D62:014010,2000 [hep-ph/0001028], and Phys.Lett.B486:86-91,2000 [hep-ph/0005124], 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 (hep-ex/0601046). The LLR approach reduces the dependence on the shape function because no model for the shape function is assumed, in contrast to the BLNP formulation used above. In hep-ph/0702072, the authors, using the BABAR result on the lepton endpoint, extract|Vub|using three prescriptions proposed by: LLR (Phys.Rev.D61:053006,2000 [hep-ph/9909404]), Neubert (Phys.Lett. B513 (2001) 88-92 [hep-ph/0104280]) and more recent calculations by Lange, Neubert and Paz (JHEP 0510 (2005) 084 [hep-ph/0508178] and JHEP 0601 (2006) 104 [hep-ph/0511098]). Here we provide a comparison among 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 three measurments, .

Description Vub [10-3] Reference
HFAG Ave. (BLNP) 4.52 +/- 0.19 +/- 0.27
HFAG Ave. (DGE) 4.46 +/- 0.20 +/- 0.20
BABAR (LLR) 4.43 +/- 0.45 +/- 0.29 Phys.Rev.Lett. 96 (2006) 221801 [hep-ex/0601046]
BABAR endpoint (LLR) 4.28 +/- 0.29 +/- 0.29 +/- 0.26 +/- 0.28 hep-ph/0702072
BABAR endpoint (weight) 4.01 +/- 0.27 +/- 0.29 +/- 0.32 +/- 0.27 hep-ph/0702072
BABAR endpoint (weight BLNP) 4.40 +/- 0.30 +/- 0.41 +/- 0.23 hep-ph/0702072

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


B -> pi l nu average for ICHEP 2006

Branching fractions of B -> 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.

Experiment / Mode BF [10-4] BF(q2<16 GeV2) [10-4] BF(q2>16 GeV2) [10-4] Reference
BABAR SL tag: B ^{+} \rightarrow \pi^{0} l^{+} \nu \times 2\tau_{0}/\tau_{+} 1.36 +/- 0.33 +/- 0.15 1.17 +/- 0.30 +/- 0.11 0.19 +/- 0.22 +/- 0.07 SL tag, Phys.Rev.Lett.97:211801,2006 [hep-ex/0607089] (input)
BABAR B_{reco} tag: B ^{+} \rightarrow \pi^{0} l^{+} \nu \times 2\tau_{0}/\tau_{+} 1.52 +/- 0.41 +/- 0.20 1.04 +/- 0.35 +/- 0.15 0.48 +/- 0.22 +/- 0.11 Breco tag, Phys.Rev.Lett.97:211801,2006 [hep-ex/0607089] (input)
BELLE SL tag: B ^{+} \rightarrow \pi^{0} l^{+} \nu \times 2\tau_{0}/\tau_{+} 1.43 +/- 0.26 +/- 0.16 1.06 +/- 0.22 +/- 0.11 0.37 +/- 0.15 +/- 0.04 SL tag, accepted by PLB [hep-ex/0604024] (input)
BELLE B_{reco} tag: B ^{+} \rightarrow \pi^{0} l^{+} \nu \times 2\tau_{0}/\tau_{+} 1.60 +/- 0.32 +/- 0.11 NA NA Preliminary, Breco tag hep-ex/0610054 (input)
BABAR SL tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu 1.12 +/- 0.25 +/- 0.10 0.83 +/- 0.22 +/- 0.08 0.29 +/- 0.15 +/- 0.04 SL tag, Phys.Rev.Lett.97:211801,2006 [hep-ex/0607089] (input)
BELLE SL tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu 1.38 +/- 0.19 +/- 0.14 1.02 +/- 0.16 +/- 0.11 0.36 +/- 0.10 +/- 0.04 SL tag, accepted by PLB [hep-ex/0604024] (input)
BABAR B_{reco} tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu 1.07 +/- 0.27 +/- 0.15 0.42 +/- 0.18 +/- 0.05 0.65 +/- 0.20 +/- 0.13 Breco tag, Phys.Rev.Lett.97:211801,2006 [hep-ex/0607089] (input)
CLEO untagged: B \rightarrow \pi l^{+} \nu 1.33 +/- 0.18 +/- 0.11 1.08 +/- 0.16 +/- 0.10 0.25 +/- 0.09 +/- 0.05 Untagged, Phys. Rev. D 68, 072003 (2003) ( hep-ex/0304015) (input)
BABAR untagged: B \rightarrow \pi l^{+} \nu 1.46 +/- 0.07 +/- 0.08 1.09 +/- 0.06 +/- 0.07 0.38 +/- 0.04 +/- 0.03 Untagged loose neutrino, Phys. Rev. Lett. 98, 091801 (2007) [hep-ex/0612020 ] (input)
BELLE B_{reco} tag: B ^{0} \rightarrow \pi^{-} l^{+} \nu 1.49 +/- 0.26 +/- 0.06 NA NA Preliminary, Breco tag hep-ex/0610054 (input)
Average: B ^{0} \rightarrow \pi^{-} l^{+} \nu 1.39 +/- 0.06 +/- 0.06 0.97 +/- 0.05 +/- 0.05 0.35 +/- 0.03 +/- 0.03 Plots: eps pdf gif   chi2/dof = 3/9 (CL = 0.95)

Vub from B -> pi l nu average for Winter 2006

Exclusive Vub determination

The partial BF quoted above along with theoretical calculations of the form factor normalization can be used to determine Vub; a few recent calculations are shown below. Note that the FNAL04 and HPQCD unquenched LQCD calculations are not entirely independent, we do not use their quenched results as they are superseded by their unquenched results. We also use the quenched LQCD result of the APE collaboration. The Ball-Zwicky calculation is based on light-cone sum rules.  At this time we do not attempt to average the Vub results or select a best value. We divide the results into two tables: the first table lists extractions of |V_ub| in q^2 regions where the theory formulation is applicable and the second lists results where these same formulations have relied on a model to extrapolate to the uncovered q^2 region.

A determination of |Vub| making use of the experimental input on the q2 dependence is under study but not yet available.

The errors on |Vub| are experimental and theoretical, respectively.

FF calculation Vub [10-3] q2 range FF norm (ps-1) Reference
Ball-Zwicky q2 < 16 3.41 +/- 0.13 +0.56-0.38 <16 GeV2 5.44 +/- 1.43 Phys. Rev. D71:014015 (2005) [hep-lat/0406232]
HPQCD q2 > 16 3.97 +/- 0.25 +0.59-0.41 >16 GeV2 1.46 +/- 0.35 Phys.Rev.D73, 074502 (2006) [hep-lat/0601021]
FNAL q2 > 16 3.55 +/- 0.22 +0.61-0.40 >16 GeV2 1.83 +/- 0.50 Nucl.Phys.Proc.Suppl.140:464-466,2005 [hep-lat/0408019]
APE q2 > 16 3.58 +/- 0.22 +1.37-0.63 >16 GeV2 1.80 +/- 0.86 Nucl. Phys. B 619 (2000) 565-587 [hep-lat/0011065]

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

FF calculation Vub [10-3] q2 range FF norm (ps-1) Reference
Ball-Zwicky full q2 3.43 +/- 0.10 +0.67-0.42 full 7.74 +/- 2.32 Phys. Rev. D71:014015 (2005) [hep-ph/0406232]
HPQCD full q2 3.89 +/- 0.12 +0.84-0.51 full 6.03 +/- 1.94 Phys.Rev.D73, 074502 (2006) [hep-lat/0601021]
FNAL full q2 3.82 +/- 0.12 +0.88-0.52 full 6.24 +/- 2.12 Nucl.Phys.Proc.Suppl.140:464-466,2005 [hep-lat/0409116]
APE full q2 3.61 +/- 0.11 +1.11-0.57 full 7.0 +/- 2.9 Nucl. Phys. B 619 (2000) 565-587 [hep-lat/0011065]

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

nada

Branching fractions of other exclusive charmless semileptonic decays

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) [hep-ex/0304019]
BABAR B+-> eta l+ nu 0.84 +/-0.27 +/- 0.21 Preliminary Breco [hep-ex/0607066]
BABAR B+-> eta' l+ nu 0.33 +/-0.60 +/- 0.30 Preliminary Breco [hep-ex/0607066]
CLEO B0-> rho- l+ nu 2.69 +/-0.41 +0.35/-0.40 +/-0.50 Phys. Rev. D 61, 052001 (2000) [hep-ex/9905056]
BABAR B0-> rho- l+ nu 2.57 +/-0.52 +/-0.59 Preliminary, Breco tag [hep-ex/0408068]
BABAR B0-> rho- l+ nu 3.29 +/-0.42 +/-0.47 +/-0.60 eConf C0304052:WG117,2003 [hep-ex/0301001]
CLEO B0-> rho- l+ nu 2.17 +/-0.34 +0.47/-0.54 +/-0.41 +/-0.01 Phys. Rev. D 68, 072003 (2003)[hep-ex/0304019]
BABAR B0-> rho- l+ nu 2.14 +/-0.21 +/-0.51 +/-0.28 Untagged, Phys .Rev. D72, 051102 (2005) [hep-ex/0507003]
BELLE B0-> rho- l+ nu 2.17 +/-0.54 +/-0.31 +/-0.08 SL tag, accepted by PLB [hep-ex/0604024]
BELLE B+-> rho0 l+ nu 1.33 +/-0.23 +/-0.17 +/-0.05 SL tag, accepted by PLB [hep-ex/0604024]
BELLE B+-> omega l+ nu 1.3 +/-0.4 +/-0.2 +/-0.3 Phys. Rev. Lett. 93:131803 (2004)[hep-ex/0402023]


Vub comparison

Inclusive and Exclusive Vub comparison

The extracted averages for the inclusive and exclusive Vub measurements are compared. Same caveats and warnings per each measurement as reported above apply.

Theory framework Vub [10-3] References
HFAG Ave. (BLNP) 4.52 +/- 0.19 +/- 0.27
HFAG Ave. (DGE) 4.46 +/- 0.20 +/- 0.20
HFAG Ave. (BLL) mx-q2 5.02 +/- 0.26 +/- 0.37
BABAR (LLR) 4.43 +/- 0.45 +/- 0.29 Phys.Rev.Lett. 96 (2006) 221801 [hep-ex/0601046]

FF calculation Vub [10-3] q2 range FF norm (ps-1) Reference
Ball-Zwicky q2 < 16 3.41 +/- 0.13 +0.56-0.38 <16 GeV2 5.44 +/- 1.43 Phys. Rev. D71:014015 (2005) [hep-lat/0406232]
HPQCD q2 > 16 3.97 +/- 0.25 +0.59-0.41 >16 GeV2 1.46 +/- 0.35 Phys.Rev.D73, 074502 (2006) [hep-lat/0601021]
FNAL q2 > 16 3.55 +/- 0.22 +0.61-0.40 >16 GeV2 1.83 +/- 0.50 Nucl.Phys.Proc.Suppl.140:464-466,2005 [hep-lat/0408019]
APE q2 > 16 3.58 +/- 0.22 +1.37-0.63 >16 GeV2 1.80 +/- 0.86 Nucl. Phys. B 619 (2000) 565-587 [hep-lat/0011065]

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


Last update: 2007/05/03 Francesca Di Lodovico (Bug fix).