Dispersive representation of the pion vector form factor in τ→ππντ decays

We propose a dispersive representation of the charged pion vector form factor that is consistent with chiral symmetry and fulfills the constraints imposed by analyticity and unitarity. Unknown parameters are fitted to the very precise data on τ − → π − π 0 ν τ decays obtained by Belle, leading to a...

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Bibliographic Details
Published in:The European physical journal. C, Particles and fields Particles and fields, 2013, Vol.73 (8)
Main Authors: Dumm, D. Gómez, Roig, P.
Format: Article
Language:English
Subjects:
Astronomy
Astrophysics and Cosmology
Elementary Particles
Hadrons
Heavy Ions
Measurement Science and Instrumentation
Nuclear Energy
Nuclear Physics
Physics
Physics and Astronomy
Quantum Field Theories
Quantum Field Theory
Regular Article - Theoretical Physics
String Theory
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Summary:We propose a dispersive representation of the charged pion vector form factor that is consistent with chiral symmetry and fulfills the constraints imposed by analyticity and unitarity. Unknown parameters are fitted to the very precise data on τ − → π − π 0 ν τ decays obtained by Belle, leading to a good description of the corresponding spectral function up to a ππ squared invariant mass s ≃1.5 GeV 2 . We determine the ρ (770) mass and width pole parameters and obtain the values of low-energy observables. The significance of isospin-breaking corrections is also discussed. For larger values of s , this representation is complemented with a phenomenological description to allow its implementation in the new TAUOLA hadronic currents.
ISSN:1434-6044
1434-6052
DOI:10.1140/epjc/s10052-013-2528-1