Related papers: On the scalar $\pi K$ form factor beyond the elast…

The rare second-class decay mode of the $\tau$ into $\eta\pi\nu$ could be observed for the first time at Belle II. It is important to try to derive a reliable evaluation of the branching fraction and of the energy distribution of this mode…

The potentialities of the production of the scalar $K\bar K$ molecules in the $\phi$ radiative decays are considered beyond the narrow resonance width approximation. It is shown that $BR(\phi\rightarrow\gamma…

We discuss a number of two loop (vertex) integrals relevant for pi K scattering at threshold. As such these are functions of two well separated mass scales, M\_pi/M\_K << 1. The method of regions allows an expansion in this mass ratio prior…

Amplitude models are applied to studies of resonance structure in $D^0\to K^0_S K^- \pi^+$ and $D^0\to K^0_S K^+ \pi^-$ decays using $pp$ collision data corresponding to an integrated luminosity of $3.0\,\mathrm{fb}^{-1}$ collected by the…

We calculate the $T$-matrices of elastic pion-nucleon ($\pi N$) scattering up to fourth order in SU(3) heavy baryon chiral perturbation theory. The pertinent low-energy constants are determined by fitting to $\pi N$ phase shifts below 200…

A new unitarization approach incorporated with chiral symmetry is established and applied to study the $\pi K$ elastic scatterings. We demonstrate that the $\kappa$ resonance exists, if the scattering length parameter in the I=1/2, J=0…

We apply the one-loop results of the $SU(3)_L\times SU(3)_R$ ChPT suplemented with the inverse amplitude method to fit the available experimental data on $\pi\pi$ and $\pi K$ scattering. With esentially only three parameters we describe…

We use the Omnes representation to obtain the q-squared dependence of the form factors f+ and f0 for semileptonic H -> pi decays from the elastic pi H -> pi H scattering amplitudes, where H denotes a B or D meson. The scattering amplitudes…

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the $K^-\pi^+$ S-wave amplitude from the decay $D^+ \to K^-\pi^+\pi^+$. The S-wave is a generic complex function to be determined…

We propose a new method to evaluate the Lellouch-L\"uscher factor which relates the $\Delta I=3/2$ $K\to\pi\pi$ matrix elements computed on a finite lattice to the physical (infinite-volume) decay amplitudes. The method relies on the use of…

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 calculate the parameters describing elastic $I=1$, $P$-wave $\pi\pi$ scattering using lattice QCD with $2+1$ flavors of clover fermions. Our calculation is performed with a pion mass of $m_\pi \approx 320\:\:{\rm MeV}$ and a lattice size…

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…

Recent results from the NA48/2 experiment are presented. The $\pi\pi$ scattering lengths $a_0^0$ and $a_0^2$ have been extracted from the cusp in the $M_{00}^2$ distribution of $K^\pm \to \pi^\pm \pi^0 \pi^0$ decays and from the $K^\pm \to…

We properly define off-shell $K\to\pi$ transition amplitudes and use them to extract information for on-shell $K\to\pi\pi$ amplitudes within Chiral Perturbation Theory. At order $p^2$ in the chiral expansion all three parameters of weak…

We present a detailed analysis of S-wave Kpi scattering up to 2 GeV, making use of the resonance chiral Lagrangian predictions together with a suitable unitarisation method. Our approach incorporates known theoretical constraints at low and…

The flavor-changing neutral current process $b\to s l^+l^-$ is beneficial to testing the standard model and hunting for new physics scenarios. In exclusive decay modes like $B\to K^*(892)l^+l^-$, the S-wave effects may not be negligible and…

A study is presented of $B^+ \to K^0_{\rm S} K^- \pi^+ K^-$ and $B^+ \to K^0_{\rm S} K^+ \pi^- K^+$ decays based on the analysis of proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV,…

We report on our reexamination of the radiative corrections to $\pi_{l2}$ and $K_{l2}$ decays. We perform a matching calculation, using a specific model with vector meson dominance in the long distance part and the parton model in the short…

We use chiral perturbation theory to evaluate the scattering amplitude for the process Pi^+ K^- to Pi^+ K^- at leading and next-to-leading orders in the chiral counting and in the presence of isospin breaking effects. We also discuss the…