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 Phys.Rev.Lett. 114 (2015), 061802.
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 |
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 | 42.19 +/- 0.78 | 4.554 +/- 0.018 | 0.464 +/- 0.076 | 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 |