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The contribution of the ρ ± vector meson to the τ → ππνγ 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 ρ ± vector meson. The absorptive pieces of the one-loop corrections to the propagators and electromagnetic vertices of the ρ ± meson and W ± 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. Modeldependent contributions to the τ → ππνγ 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 ρ magnetic dipole moment.

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“…A model independent measurement of its mass and width can only be obtained by identifying the pole position of the S-matrix amplitude [7,8].…”

Section: Introductionmentioning

confidence: 99%

Gauge invariance and finite width effects in radiative two-pionτlepton decay

Castro

Sánchez

2000

Phys. Rev. D

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“…A similar parametrization insensitivity of the mass and width defined from the complex pole position has been noted in Ref. [6]. Note, however, for this latter choice, that the phase shift would not be π/2 at s = m ρ 2 and that the resultant form factor near s = m 2 ρ would not be of Breit-Wigner form.…”

Section: Resultsmentioning

confidence: 62%

“…Moreover, the ρ mass and width are themselves sensitive to the choice of F ρ (s) [1][2][3], and we wish to determine the systematic error in these quantities as well. Maltman et al have discussed the separation ofΠ ρω (s) into two contributions: one from the direct coupling of ω → 2π and the other from mixing, ω → ρ → 2π [6,4,5]. Such a separation is model dependent, and we shall not pursue it further.…”

Section: Introductionmentioning

confidence: 98%

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Erratum: Rho-omega mixing and the pion form factor in the timelike region [Phys. Rev. D57, 2716 (1998)]

Gardner¹,

O'Connell²

2000

Phys. Rev. D

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“…There are however, former fit values for the Orsay phase which give information on its model dependence [45][46][47]. The reference value we choose is somewhat median and has the virtue to reproduce the threshold behavior predicted by Chiral Perturbation Theory with a good accuracy [26] ; however, from the other references just quoted, one might conclude that systematic errors of about 10…”

Section: Radiative and Vector Decays Of Light Mesonsmentioning

confidence: 88%

Isospin Symmetry Breaking within the HLS Model: A Full (rho, omega, phi) Mixing Scheme

O'Connell¹

2001

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We study the way isospin symmetry violation can be generated within the Hidden Local Symmetry (HLS) Model. We show that isospin symmetry breaking effects on pseudoscalar mesons naturally induces correspondingly effects within the physics of vector mesons, through kaon loops. In this way, one recovers all features traditionally expected from ρ−ω mixing and one finds support for the Orsay phase modelling of the e + e − → π + π − amplitude. We then examine an effective procedure which generates mixing in the whole ρ, ω, φ sector of the HLS Model. The corresponding model allows us to account for all two body decays of light mesons accessible to the HLS model in modulus and phase, leaving aside the ρ → ππ and K * → Kπ modes only, which raise a specific problem. Comparison with experimental data is performed and covers modulus and phase information ; this represents 26 physics quantities successfully described with very good fit quality within a constrained model which accounts for SU(3) breaking, nonet symmetry breaking in the pseudoscalar sector and, now, isospin symmetry breaking.

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Mass and width of theρ0from anS-matrix approach toe+

Cited by 50 publications

References 17 publications

Gauge invariance and finite width effects in radiative two-pionτlepton decay

Gauge invariance and finite width effects in radiative two-pionτlepton decay

Erratum: Rho-omega mixing and the pion form factor in the timelike region [Phys. Rev. D57, 2716 (1998)]

Isospin Symmetry Breaking within the HLS Model: A Full (rho, omega, phi) Mixing Scheme

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