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Matthias Jamin - One of the best experts on this subject based on the ideXlab platform.

  • the kPi Vector form factor and constraints from kl3 decays
    arXiv: High Energy Physics - Phenomenology, 2011
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    The slope and curvature parameters of the $K\Pi$ Vector form factor, $F_+^{K\Pi}$, are fitted to the data on $\tauKPi$ and $K_{l3}$ decays yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. The pole position of the $K^*(892)^\pm$ is found to be at $m_{K^*(892)^\pm}= 892.0\pm 0.5$ MeV and $\Gamma_{K^*(892)^\pm}= 46.5 \pm1.1$ MeV. The phase-space integrals relevant for $K_{l3}$ analyses and the $P$-wave isosPin-1/2 $K\Pi$ phase-shift threshold parameters are also calculated.

  • constraining the kPi Vector form factor by tau k Pi nu_tau and k_l3 decay data
    arXiv: High Energy Physics - Phenomenology, 2010
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    A subtracted dispersive representation of the $K\Pi$ Vector form factor, $F_+^{K\Pi}$, is used to fit the Belle spectrum of $\tauKPi$ decays incorporating constraints from results on $K_{l3}$ decays. Through the use of three subtractions, the slope and curvature of $F_+^{K\Pi}$ are obtained directly from the data yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. The phase-space integrals relevant for $K_{l3}$ analyses are calculated. Additionally, from the pole position on the second Riemann sheet the mass and width of the $K^*(892)^\pm$ are found to be $m_{K^*(892)^\pm}= 892.0\pm 0.5$ MeV and $\Gamma_{K^*(892)^\pm}= 46.5 \pm 1.1$ MeV. Finally, we study the $P$-wave isosPin-1/2 $K\Pi$ phase-shift and its threshold parameters.

  • k Pi Vector form factor constrained by tau k Pi nu_tau and k_l3 decays
    arXiv: High Energy Physics - Phenomenology, 2010
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Dispersive representations of the KPi Vector and scalar form factors are used to fit the spectrum of tau ---> K Pi nu_tau obtained by the Belle collaboration incorporating constraints from results for K_l3 decays. The slope and curvature of the Vector form factor are obtained directly from the data through the use of a three-times-subtracted dispersion relation. We find $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. From the pole position on the second Riemann sheet the mass and width of the $K^*(892)^{\pm}$ are found to be $m_{K^*(892)^\pm}=892.0\pm 0.5$~MeV and $\Gamma_{K^*(892)^\pm}=46.5\pm 1.1$~MeV. The phase-space integrals needed for K_l3 decays are calculated as well. Furthermore, the KPi isosPin-1/2 P-wave threshold parameters are derived from the phase of the Vector form factor. For the scattering length and the effective range we find respectively $a_{1}^{1/2}\,= ( 0.166\pm 0.004)\,m_\Pi^{-3}$ and $b_{1}^{1/2}\,=( 0.258\pm 0.009)\,m_\Pi^{-5}$.

  • dispersive representation of the k Pi Vector form factor and fits to tau k Pi nu tau and ke3 data
    arXiv: High Energy Physics - Phenomenology, 2009
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Recently, we introduced several dispersive representations for the Vector $K\Pi$ form factor and fitted them to the Belle spectrum of $\tau \to K \Pi \nu_\tau$. Here, we briefly present the model and discuss the results for the slope and curvature of $F_+(s)$ arising from the best fit. Furthermore, we compare the pole position of the charged $K^*(892)$ computed from our model with other results in the literature. Finally, we discuss the prospects of a simultaneous fit to $\tau \to K \Pi \nu_\tau$ and $K_{e3}$ spectra.

  • k Pi Vector form factor dispersive constraints and tau nu_tau k Pi decays
    arXiv: High Energy Physics - Phenomenology, 2008
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Recent experimental data for the differential decay distribution of the decay $\tau^-\to\nu_\tau K_S\Pi^-$ by the Belle collaboration are described by a theoretical model which is composed of the contributing Vector and scalar form factors $F_+^{K\Pi}(s)$ and $F_0^{K\Pi}(s)$. 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 $F_+^{K\Pi}(s)$ in the complex $s$-plane, can be extracted, with the result $M_{K^*}=892.0 \pm 0.9 $MeV and $\Gamma_{K^*}=46.2 \pm 0.4 $MeV. Finally, employing the three-subtracted dispersion relation allows to determine the slope and curvature parameters $\lambda_+^{'}=(24.7\pm 0.8)\cdot 10^{-3}$ and $\lambda_+^{''}=(12.0\pm 0.2)\cdot 10^{-4}$ of the Vector form factor $F_+^{K\Pi}(s)$ directly from the data.

Diogo Boito - One of the best experts on this subject based on the ideXlab platform.

  • the kPi Vector form factor and constraints from kl3 decays
    arXiv: High Energy Physics - Phenomenology, 2011
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    The slope and curvature parameters of the $K\Pi$ Vector form factor, $F_+^{K\Pi}$, are fitted to the data on $\tauKPi$ and $K_{l3}$ decays yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. The pole position of the $K^*(892)^\pm$ is found to be at $m_{K^*(892)^\pm}= 892.0\pm 0.5$ MeV and $\Gamma_{K^*(892)^\pm}= 46.5 \pm1.1$ MeV. The phase-space integrals relevant for $K_{l3}$ analyses and the $P$-wave isosPin-1/2 $K\Pi$ phase-shift threshold parameters are also calculated.

  • constraining the kPi Vector form factor by tau k Pi nu_tau and k_l3 decay data
    arXiv: High Energy Physics - Phenomenology, 2010
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    A subtracted dispersive representation of the $K\Pi$ Vector form factor, $F_+^{K\Pi}$, is used to fit the Belle spectrum of $\tauKPi$ decays incorporating constraints from results on $K_{l3}$ decays. Through the use of three subtractions, the slope and curvature of $F_+^{K\Pi}$ are obtained directly from the data yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. The phase-space integrals relevant for $K_{l3}$ analyses are calculated. Additionally, from the pole position on the second Riemann sheet the mass and width of the $K^*(892)^\pm$ are found to be $m_{K^*(892)^\pm}= 892.0\pm 0.5$ MeV and $\Gamma_{K^*(892)^\pm}= 46.5 \pm 1.1$ MeV. Finally, we study the $P$-wave isosPin-1/2 $K\Pi$ phase-shift and its threshold parameters.

  • k Pi Vector form factor constrained by tau k Pi nu_tau and k_l3 decays
    arXiv: High Energy Physics - Phenomenology, 2010
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Dispersive representations of the KPi Vector and scalar form factors are used to fit the spectrum of tau ---> K Pi nu_tau obtained by the Belle collaboration incorporating constraints from results for K_l3 decays. The slope and curvature of the Vector form factor are obtained directly from the data through the use of a three-times-subtracted dispersion relation. We find $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. From the pole position on the second Riemann sheet the mass and width of the $K^*(892)^{\pm}$ are found to be $m_{K^*(892)^\pm}=892.0\pm 0.5$~MeV and $\Gamma_{K^*(892)^\pm}=46.5\pm 1.1$~MeV. The phase-space integrals needed for K_l3 decays are calculated as well. Furthermore, the KPi isosPin-1/2 P-wave threshold parameters are derived from the phase of the Vector form factor. For the scattering length and the effective range we find respectively $a_{1}^{1/2}\,= ( 0.166\pm 0.004)\,m_\Pi^{-3}$ and $b_{1}^{1/2}\,=( 0.258\pm 0.009)\,m_\Pi^{-5}$.

  • dispersive representation of the k Pi Vector form factor and fits to tau k Pi nu tau and ke3 data
    arXiv: High Energy Physics - Phenomenology, 2009
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Recently, we introduced several dispersive representations for the Vector $K\Pi$ form factor and fitted them to the Belle spectrum of $\tau \to K \Pi \nu_\tau$. Here, we briefly present the model and discuss the results for the slope and curvature of $F_+(s)$ arising from the best fit. Furthermore, we compare the pole position of the charged $K^*(892)$ computed from our model with other results in the literature. Finally, we discuss the prospects of a simultaneous fit to $\tau \to K \Pi \nu_\tau$ and $K_{e3}$ spectra.

  • k Pi Vector form factor dispersive constraints and tau nu_tau k Pi decays
    arXiv: High Energy Physics - Phenomenology, 2008
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Recent experimental data for the differential decay distribution of the decay $\tau^-\to\nu_\tau K_S\Pi^-$ by the Belle collaboration are described by a theoretical model which is composed of the contributing Vector and scalar form factors $F_+^{K\Pi}(s)$ and $F_0^{K\Pi}(s)$. 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 $F_+^{K\Pi}(s)$ in the complex $s$-plane, can be extracted, with the result $M_{K^*}=892.0 \pm 0.9 $MeV and $\Gamma_{K^*}=46.2 \pm 0.4 $MeV. Finally, employing the three-subtracted dispersion relation allows to determine the slope and curvature parameters $\lambda_+^{'}=(24.7\pm 0.8)\cdot 10^{-3}$ and $\lambda_+^{''}=(12.0\pm 0.2)\cdot 10^{-4}$ of the Vector form factor $F_+^{K\Pi}(s)$ directly from the data.

Rafel Escribano - One of the best experts on this subject based on the ideXlab platform.

  • the kPi Vector form factor and constraints from kl3 decays
    arXiv: High Energy Physics - Phenomenology, 2011
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    The slope and curvature parameters of the $K\Pi$ Vector form factor, $F_+^{K\Pi}$, are fitted to the data on $\tauKPi$ and $K_{l3}$ decays yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. The pole position of the $K^*(892)^\pm$ is found to be at $m_{K^*(892)^\pm}= 892.0\pm 0.5$ MeV and $\Gamma_{K^*(892)^\pm}= 46.5 \pm1.1$ MeV. The phase-space integrals relevant for $K_{l3}$ analyses and the $P$-wave isosPin-1/2 $K\Pi$ phase-shift threshold parameters are also calculated.

  • constraining the kPi Vector form factor by tau k Pi nu_tau and k_l3 decay data
    arXiv: High Energy Physics - Phenomenology, 2010
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    A subtracted dispersive representation of the $K\Pi$ Vector form factor, $F_+^{K\Pi}$, is used to fit the Belle spectrum of $\tauKPi$ decays incorporating constraints from results on $K_{l3}$ decays. Through the use of three subtractions, the slope and curvature of $F_+^{K\Pi}$ are obtained directly from the data yielding $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. The phase-space integrals relevant for $K_{l3}$ analyses are calculated. Additionally, from the pole position on the second Riemann sheet the mass and width of the $K^*(892)^\pm$ are found to be $m_{K^*(892)^\pm}= 892.0\pm 0.5$ MeV and $\Gamma_{K^*(892)^\pm}= 46.5 \pm 1.1$ MeV. Finally, we study the $P$-wave isosPin-1/2 $K\Pi$ phase-shift and its threshold parameters.

  • k Pi Vector form factor constrained by tau k Pi nu_tau and k_l3 decays
    arXiv: High Energy Physics - Phenomenology, 2010
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Dispersive representations of the KPi Vector and scalar form factors are used to fit the spectrum of tau ---> K Pi nu_tau obtained by the Belle collaboration incorporating constraints from results for K_l3 decays. The slope and curvature of the Vector form factor are obtained directly from the data through the use of a three-times-subtracted dispersion relation. We find $\lambda_+'=(25.49 \pm 0.31) \times 10^{-3}$ and $\lambda_+"= (12.22 \pm 0.14) \times 10^{-4}$. From the pole position on the second Riemann sheet the mass and width of the $K^*(892)^{\pm}$ are found to be $m_{K^*(892)^\pm}=892.0\pm 0.5$~MeV and $\Gamma_{K^*(892)^\pm}=46.5\pm 1.1$~MeV. The phase-space integrals needed for K_l3 decays are calculated as well. Furthermore, the KPi isosPin-1/2 P-wave threshold parameters are derived from the phase of the Vector form factor. For the scattering length and the effective range we find respectively $a_{1}^{1/2}\,= ( 0.166\pm 0.004)\,m_\Pi^{-3}$ and $b_{1}^{1/2}\,=( 0.258\pm 0.009)\,m_\Pi^{-5}$.

  • dispersive representation of the k Pi Vector form factor and fits to tau k Pi nu tau and ke3 data
    arXiv: High Energy Physics - Phenomenology, 2009
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Recently, we introduced several dispersive representations for the Vector $K\Pi$ form factor and fitted them to the Belle spectrum of $\tau \to K \Pi \nu_\tau$. Here, we briefly present the model and discuss the results for the slope and curvature of $F_+(s)$ arising from the best fit. Furthermore, we compare the pole position of the charged $K^*(892)$ computed from our model with other results in the literature. Finally, we discuss the prospects of a simultaneous fit to $\tau \to K \Pi \nu_\tau$ and $K_{e3}$ spectra.

  • k Pi Vector form factor dispersive constraints and tau nu_tau k Pi decays
    arXiv: High Energy Physics - Phenomenology, 2008
    Co-Authors: Diogo Boito, Rafel Escribano, Matthias Jamin
    Abstract:

    Recent experimental data for the differential decay distribution of the decay $\tau^-\to\nu_\tau K_S\Pi^-$ by the Belle collaboration are described by a theoretical model which is composed of the contributing Vector and scalar form factors $F_+^{K\Pi}(s)$ and $F_0^{K\Pi}(s)$. 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 $F_+^{K\Pi}(s)$ in the complex $s$-plane, can be extracted, with the result $M_{K^*}=892.0 \pm 0.9 $MeV and $\Gamma_{K^*}=46.2 \pm 0.4 $MeV. Finally, employing the three-subtracted dispersion relation allows to determine the slope and curvature parameters $\lambda_+^{'}=(24.7\pm 0.8)\cdot 10^{-3}$ and $\lambda_+^{''}=(12.0\pm 0.2)\cdot 10^{-4}$ of the Vector form factor $F_+^{K\Pi}(s)$ directly from the data.

K Ghorbani - One of the best experts on this subject based on the ideXlab platform.

Cecilia Tarantino - One of the best experts on this subject based on the ideXlab platform.

  • K -> Pi Vector form factor with N_f=2+1+1 Twisted Mass fermions
    arXiv: High Energy Physics - Lattice, 2014
    Co-Authors: N. Carrasco, Vittorio Lubicz, Silvano Simula, P. Lami, E. Picca, Lucia Riggio, Cecilia Tarantino
    Abstract:

    We present a lattice QCD determination of the Vector form factor of the kaon semileptonic decay K -> Pi l nu which is relevant for the extraction of the CKM matrix element |V_{us}| from experimental data. Our result is based on the gauge configurations produced by the European Twisted Mass Collaboration with N_f=2+1+1 dynamical fermions. We simulated at three different values of the lattice spacing and with Pion masses as small as 210 MeV. Our preliminary estimate for the Vector form factor at zero momentum transfer is f_+(0)=0.9683(65), where the uncertainty is both statistical and systematic. By combining our result with the experimental value of f_+(0)|V_{us}| we obtain |V_{us}|=0.2234(16), which satisfies the unitarity constraint of the Standard Model at the permille level.