Related papers: K pi vector form factor, dispersive constraints an…
Two pion effective mass and helicity angle distributions in the charged B-meson decays into three charged pions are studied. The weak decay amplitudes are calculated in the framework of the QCD factorization approximation. The strong…
We present an analysis of the decay $D^{+} \to K^{-} \pi^+ e^+ \nu_e$ based on data collected by the BESIII experiment at the $\psi(3770)$ resonance. Using a nearly background-free sample of 18262 events, we measure the branching fraction…
The polarization effects in the one-meson radiative decay of the polarized $\tau$ lepton, $\tau^-\to\pi^-\gamma\nu_{\tau}$, have been investigated. We present the analytical results for the $t-$distribution of the partial differential…
The recent precise measurements of the $e^+e^-\to K_SK_L$ and $e^+e^-\to K^+K^-$ cross sections and the hadronic spectral function of the $\tau^-\to K^-K_S\nu_\tau$ decay are used to extract the isoscalar and isovector electromagnetic kaon…
We consider the evaluation of the $\eta\pi$ isospin-violating vector and scalar form factors relying on a systematic application of analyticity and unitarity, combined with chiral expansion results. It is argued that the usual analyticity…
Rigorous bounds are established for the expansion coefficients governing the shape of semileptonic K-->pi form factors. The constraints enforced by experimental data from tau-->K pi nu eliminate uncertainties associated with model…
The decays tau -> 3 pi + nu(tau) are analyzed at one loop order in the framework of Generalized Chiral Perturbation Theory, in order to test the sensitivity to the size of spontaneous chiral symmetry breaking parameters, contained in the…
We report a measurement of the branching fraction for tau- -> pi- pi0 nu and the invariant mass spectrum of the resulting pi- pi0 system using 72.2 /fb of data recorded by the Belle detector at the KEKB e+e- collider. The branching fraction…
In this work, we make a study of the $\tau^- \to \omega\pi^-\nu_\tau$ decay in the framework of low-energy effective field theory. The $J^{\mathcal{P}G}$ decompositions of the quark currents and the $\omega\pi$ final state show that,…
The first measurements of the coherence factor R_{K_S^0K\pi} and the average strong--phase difference \delta^{K_S^0K\pi} in D^0 \to K_S^0 K^\mp\pi^\pm decays are reported. These parameters can be used to improve the determination of the…
We report experimental details and results of a new measurement of the decay K+ -> pi+pi-e+nue (Ke4}. A sample of more than 400,000 Ke4 events with low background has been collected by Experiment 865 at the Brookhaven Alternate Gradient…
Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay $D^0 \to \bar{K}^0\pi^-\mu^+\nu$. Using a model that includes a $\bar{K}^0 \pi^-$ S-wave component, we…
The charged $K_{\ell 4}$ decay, $K^+\to\pi^+\pi^-\ell^+\nu_{\ell}$ is studied in the framework of chiral perturbation theory based on the effective Lagrangian including mesons, photons, and leptons. We give analytic expressions for the two…
In the presence of photons, the neutral $K_{\ell 4}$ decay, $K^0\to\pi^0\pi^-\ell^+\nu_\ell$, can be parameterized in terms of three vectorial, one anomalous, and one tensorial form factors. We present here analytic expressions of two…
Rare B decays to three charged kaons are analysed. The weak decay amplitudes are derived in the QCD factorization approach. The strong final state interactions between pairs of kaons are described using the kaon scalar and vector form…
Recently, the Belle collaboration reported the first measurements of the $\tau^- \to\nu_{\tau}\pi^-e^+e^-$ branching fraction and the spectrum of the pion-dielectron system. In an analysis previous to Belle's results, we evaluated this…
We present a lattice QCD determination of the vector and scalar form factors of the semileptonic $K \to \pi \ell \nu$ decay which are relevant for the extraction of the CKM matrix element $|V_{us}|$ from experimental data. Our results are…
We report a study of the semileptonic decay $D^0 \rightarrow \bar{K}^0\pi^-\mu^+\nu_{\mu}$ based on a sample of $7.9~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy of 3.773~GeV with the BESIII detector…
Motivated by the $2.8\sigma$ discrepancy observed between the BaBar measurement and the Standard Model prediction of the CP asymmetry in $\tau\to K_S\pi\nu_\tau$ decays, as well as the prospects of future measurements at Belle II, we…
In the $U(3) \times U(3)$ quark NJL model, $\tau$ lepton decays with the production of scalar mesons $f_0(\pi,K])$ and neutrinos are studied, where $f_0=f_0(500), f_0(980)$. It is shown that these decays mainly occur via contact channels…