K pi vector form factor, dispersive constraints and tau -> nu_tau K pi decays

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dc.creatorBoito, Diogo R.
dc.creatorEscribano, Rafel
dc.creatorJamin, Matthias
dc.date2008-07-30
dc.date2008-12-02
dc.date.accessioned2026-07-07T12:46:55Z
dc.date.available2026-07-07T12:46:55Z
dc.descriptionRecent experimental data for the differential decay distribution of the decay $τ^-\toν_τK_Sπ^-$ by the Belle collaboration are described by a theoretical model which is composed of the contributing vector and scalar form factors $F_+^{Kπ}(s)$ and $F_0^{Kπ}(s)$. Both form factors are constructed such that they fulfil constraints posed by analyticity and unitarity. A good description of the experimental measurement is achieved by incorporating two vector resonances and working with a three-times subtracted dispersion relation in order to suppress higher-energy contributions. The resonance parameters of the charged $K^*(892)$ meson, defined as the pole of $F_+^{Kπ}(s)$ in the complex $s$-plane, can be extracted, with the result $M_{K^*}=892.0 \pm 0.9 $MeV and $Γ_{K^*}=46.2 \pm 0.4 $MeV. Finally, employing the three-subtracted dispersion relation allows to determine the slope and curvature parameters $λ_+^{'}=(24.7\pm 0.8)\cdot 10^{-3}$ and $λ_+^{''}=(12.0\pm 0.2)\cdot 10^{-4}$ of the vector form factor $F_+^{Kπ}(s)$ directly from the data.
dc.description16 pages, 1 figure, version to appear in Eur. Phys. J. C
dc.identifierhttps://arxiv.org/abs/0807.4883
dc.identifierhttp://arxiv.org/abs/0807.4883
dc.identifierEur.Phys.J.C59:821-829,2009
dc.identifierdoi:10.1140/epjc/s10052-008-0834-9
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/221548
dc.subjectHigh Energy Physics - Phenomenology
dc.subjectHigh Energy Physics - Experiment
dc.subjectHigh Energy Physics - Lattice
dc.subjectNuclear Theory
dc.titleK pi vector form factor, dispersive constraints and tau -> nu_tau K pi decays
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