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X. C. Song

Publications and source records attributed to X. C. Song.

2 recordsLinked to original sources

Anomalous magnetic and electric moments of $τ$ and lepton flavor mixing matrix in effective lagrangian approach

In an effective lagrangian approach [EM97] to new physics, the authors in ref. [HL99] pushed tau anomalous magnetic and electric dipole moments (AMDM and EDM) down to $10^{-11}$ and $10^{-25} e cm$ by using a Fritzsch-Xing lepton mass matrix ansatz. In this note, we find that, in this approach, there exists the connection between $τ$ AMDM and EDM and the lepton flavor mixing matrix. By using the current neutrino oscillation experimental results, we investigate the parameter space of lepton mixing angles to $τ$ AMDM and EDM. We can obtain the same or smaller bounds of $δa_τ$ and $d_τ$ acquired in ref. [HL99] and constrain $θ_l$ (the mixing angle obtained by long-baseline neutrino oscillation experiments) from $τ$ AMDM and EDM.

hep-ph

A Critical Examination to the Unitarized $ππ$ Scattering Chiral Amplitudes

We discuss the Padé approximation to the $ππ$ scattering amplitudes in 1--loop chiral perturbation theory. The approximation restores unitarity and can reproduce the correct resonance poles, but the approximation violates crossing symmetry and produce spurious poles on the complex $s$ plane and therefore plagues its predictions on physical quantities at quantitative level. However we find that one virtual state in the IJ=20 channel may have physical relevance.

hep-ph