Gauge invariance and finite width effects in radiative two-pion tau lepton decay

Abstract

The contribution of the rho^{\pm} vector meson to the tau -> pi pi nu gamma decay is considered as a potential source for the determination of the magnetic dipole moment of this light vector meson. In order to keep gauge-invariance of the whole decay amplitude, a procedure similar to the fermion loop-scheme for charged gauge bosons is implemented to incorporate the finite width effects of the rho^{\pm} vector meson. The absorptive pieces of the one-loop corrections to the propagators and electromagnetic vertices of the rho^{\pm} meson and W^{\pm} gauge boson have identical forms in the limit of massless particles in the loops, suggesting this to be a universal feature of spin-one unstable particles. Model-dependent contributions to the tau -> pi pi nu gamma decay are suppressed by fixing the two-pion invariant mass distribution at the rho meson mass value. The resulting photon energy and angular distribution is relatively sensitive to the effects of the rho magnetic dipole moment.

22 pages, 4 postscript figures, references and comments on relevance of perturbative treatment of rho electromagnetic vertex are added, accepted for pub. in Phys. Rev. D

References in corpus (2)

• Vector-meson magnetic dipole moment effects in radiative tau decays
• Effects of anomalous charged current dipole moments of the tau on the decay ${\tau }^{-}\to {\nu }_{\tau }{\pi }^{-}{\pi }^0$

Cited by in corpus (14)

• Finite-Width Effects in Top Quark Production at Hadron Colliders
• Determination of the Delta++ magnetic dipole moment
• Magnetic dipole moment of the ${\Delta }^{+}$(1232) from the $\gamma p\to \gamma {\pi }^{0}p$ reaction
• Elastic and radiative pi^+p scattering and properties of the Delta^{++} resonance
• Radiative two-pion decay of the tau lepton
• Finite width induced modification to the electromagnetic form factors of spin-1 particles
• Beyond the soft photon approximation in radiative production and decay of charged vector mesons
• $B\to \rho$ semileptonic decays and $|V_{ub}|$
• Convolution formula and finite W boson width effects in the top quark width
• Absorptive corrections for vector mesons. Matching to complex mass scheme and longitudinal corrections
• Closing the Gap on $R_{D^{\ast }}$ by including longitudinal effects
• ${\tau }^{-}\to {\pi }^{-}\eta {\nu }_{\tau }$ decay induced by QED one-loop effects
• Gauge invariance, radiative interferences and properties of vector mesons
• Properties of vector mesons in four pseudoscalars electroproduction