The HLS approach to $(g-2{)}_{\mu }$~: A Solution to the "$\tau$ versus $e^{+}{e}^{-}$" Puzzle

Abstract

The Hidden Local Symmetry (HLS) Model provides a framework able to encompass several physical processes and gives a unfied description of these in an energy range extending up to the $\varphi$ mass. Supplied with appropriate symmetry breaking schemes, the HLS Model gives a broken Effective Lagrangian (BHLS). The BHLS Lagrangian gives rise to a fit procedure in which a simultaneous description of the $e^{+}{e}^{-}$ annihilations to ${\pi }^{+}{\pi }^{-}$, ${\pi }^0\gamma$, $\eta \gamma$, ${\pi }^{+}{\pi }^{-}{\pi }^0$, $K^{+}{K}^{-}$, $K_L{K}_S$ and of the dipion spectrum in the decay ${\tau }^{\pm }\to {\pi }^{\pm }{\pi }^0\nu$ can be performed. Supplemented with a few pieces of information on the ${\rho }^0-\omega -\varphi$ system, the $\tau$ dipion spectrum is shown to predict accurately the pion form factor in $e^{+}{e}^{-}$ annihilations. Physics results derived from global fits involving or excluding the $\tau$ dipion spectra are found consistent with each others. Therefore, no obvious mismatch between the $\tau$ and $e^{+}{e}^{-}$ physics properties arises and the $\tau -e^{+}{e}^{-}$ puzzle vanishes within the broken HLS Model.

talk given at the Workshop on Flavour changing and conserving processes 2015, Anacapri, Italy, september 10-12, 2015 and at PHOTON 2015, Novosibirsk, Russia June 15 - 19, 2015

References in corpus (4)

• Update of the e^+e^-\toπ^+π^- cross section measured by SND detector in the energy region 400<\sqrt{s}<1000 MeV
• Measurement of sigma(e+ e- -> pi+ pi-) from threshold to 0.85 GeV^2 using Initial State Radiation with the KLOE detector
• The hadronic contribution to (g-2) of the muon
• The Dipion Mass Spectrum In e+e- Annihilation and tau Decay: A Dynamical (rho0, omega, phi) Mixing Approach

Cited by in corpus (3)

• On the precision of a data-driven estimate of hadronic light-by-light scattering in the muon g-2: pseudoscalar-pole contribution
• BHLS${}_2$, a New Breaking of the HLS Model and its Phenomenology
• From Hadronic Cross Section to the measurement of the Vacuum Polarization at KLOE: a fascinating endeavour