It is based on calculations in the Shape Function Scheme (see hep-ph/0504071) and Dressed Gluon Exponentiation (DGE) (see hep-ph/0502159) approach.

Experiment | Photon Moments | References |
---|---|---|

BABAR | First Moment and Variance at 1.9 GeV | hep-ex/0508004 (Phys.Rev. D72 (2005) 052004) |

BABAR | First Moment and Variance at 1.9 GeV | hep-ex/0507001 |

Belle | First Moment and Variance at 1.8 GeV | hep-ex/0403004 (Phys. Rev. Lett 93(2004)061803) hep-ex/0508005 |

CLEO | First Moment and Variance at 2.0 GeV | hep-ex/0403052 (Phys.Rev.Lett. 87 (2001) 251807) |

We fit the moments using the SF scheme and the DGE approach. In case
of the DGE approach, we have assumed theoretical errors coming from the
matching coefficient (between m_b (default) and m_b/2), alphas
(0.1176+/-0.002), the 3/2 renormalon residue (C=0.1 and C=10 with C=1
(default)) and nf (3 and 4 (default)).

Theoretical Calculation | mb | mu_pi^2 | Correlation | Chi^2/Ndof | Plot |
---|---|---|---|---|---|

SF Scheme | mb = 4.56 +- 0.05GeV | mu_pi^2 = 0.28 +- 0.08 GeV^2 | rho = -0.855 | chi2/Ndof = 1.02/6 | Delta Chi^2=1 Ellipse |

DGE | mb = 4.17 +- 0.05 GeV | chi2/Ndof = 1.9/5. | Overlay of theoretical predictions from fit to the moment |

Last update: 2006/03/05 Francesca Di Lodovico