Physics – High Energy Physics – High Energy Physics - Phenomenology
Scientific paper
2007-01-19
Nucl.Phys.Proc.Suppl.169:288-296,2007
Physics
High Energy Physics
High Energy Physics - Phenomenology
9 pages, 7 figures, invited talk at the Tau06 International Workshop, Pisa, September 19-22 2006
Scientific paper
10.1016/j.nuclphysbps.2007.03.02
The evaluation of the hadronic contribution to the muon magnetic anomaly $a_\mu$ is revisited, taking advantage of new experimental data on $e^+e^-$ annihilation into hadrons: SND and CMD-2 for the $\pi^+\pi^-$ channel, and \babar for multihadron final states. Discrepancies are observed between KLOE and CMD-2/SND data, preventing one from averaging all the $e^+e^-$ results. The long-standing disagreement between spectral functions obtained from $\tau$ decays and $e^+e^-$ annihilation is still present, and not accounted by isospin-breaking corrections, for which new estimates have been presented. The updated Standard Model value for $a_\mu$ based on $e^+e^-$ annihilation data is now reaching a precision better than experiment, and it disagrees with the direct measurement from BNL at the 3.3$\sigma$ level, while the $\tau$-based estimate is in much better agreement. The $\tau$/$e^+e^-$ discrepancy, best revealed when comparing the measured branching fraction for $\tau^- \to \pi^- \pi^0 \nu_\tau$ to its prediction from the isospin-breaking-corrected $e^+e^-$ spectral function, remains a serious problem to be understood.
No associations
LandOfFree
The hadronic contribution to (g-2) of the muon does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The hadronic contribution to (g-2) of the muon, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The hadronic contribution to (g-2) of the muon will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-70744