Related papers: Data-driven dispersive analysis of the $\pi \pi$ a…
We investigate the $D_{s}^{+} \rightarrow K^{+} K^{-} \pi^{+}$ decay theoretically with the final state interactions, which is based on the chiral unitary approach and takes into account the external and internal $W$-emission mechanisms at…
We present a novel analysis of the $\pi N$ scattering amplitude in Lorentz covariant baryon chiral perturbation theory renormalized in the extended-on-mass-shell scheme. This amplitude, valid up to $\mathcal{O}(p^3)$ in the chiral…
We present a set of once subtracted dispersion relations which implement crossing symmetry conditions for the $\pi\pi$ scattering amplitudes below 1 GeV. We compare and discuss the results obtained for the once and twice subtracted…
K-matrix analysis of the $00^{++}$ wave is performed in the channels $\pi\pi,~K\bar K,~\eta\eta$ and $4\pi$ in the mass region up to 1550 MeV. The fit is based on the following data: $p\bar p ~(at~rest)\to \pi^0\pi^0\pi^0$,…
The analysis of high-precision $\pi^{\pm}p \to \pi^{\pm}p$ cross section data from the EPECUR Collaboration based on the multichannel $K$-matrix approach is presented.The sharp structures seen in these data are studied in terms of both…
The pole structure of the current GW/SAID partial-wave analysis of elastic $\pi N$ scattering and $\eta N$ production data is studied. Pole positions and residues are extracted from both the energy-dependent and single-energy fits, using…
We evaluate the matrix elements for the processes pi^0 K^0 -> pi^0 K^0 and pi^- K^+ -> pi^0 K^0 in the presence of isospin breaking terms at leading and next-to-leading order. As a direct application the releveant combination of the S-wave…
The scattering of $\gamma \pi \to \pi \pi$ is studied using the axial anomaly, elastic unitarity, analyticity and crossing symmetry. Using the technique to derive the Roy's equation, an integral equation for the P-wave amplitude is obtained…
In this article we study resonances and surface waves in $\pi^+$--p scattering. We focus on the sequence whose spin-parity values are given by $J^p = {3/2}^+,{7/2}^+, {11/2}^+, {15/2}^+,{19/2}^+$. A widely-held belief takes for granted that…
We derive a method to calculate the multi-channel K matrix applicable to a broad class of models in which mesons linearly couple to the quark core. The method is used to calculate pion scattering amplitudes in the energy region of low-lying…
Excited hadrons are seen as resonances in the scattering of lighter stable hadrons like $\pi$, $K$ and $\eta$. Many decay into multiple final states necessitating coupled-channel analyses. Recently it has become possible to obtain…
We derive dispersion relations for $K\to\pi\pi$ decay, using the Lehmann-Symanzik-Zimmermann formalism, which allows the analytic continuation of the amplitudes with respect to the momenta of the external particles. No off-shell…
New solutions on the scalar -- isoscalar $\pi\pi$ phase shifts are analysed together with previous $K\bar{K}$ results using a separable potential model of three coupled channels ($\pi\pi$, $K\bar{K}$ and an effective $2\pi 2\pi$ system).…
Lattice QCD spectra can be used to constrain partial-wave scattering amplitudes that, while satisfying unitarity, do not have to respect crossing symmetry and analyticity. This becomes a particular problem when extrapolated far from real…
The elastic $I=1/2$, $s$- and $p$-wave kaon-pion scattering amplitudes are calculated using a single ensemble of anisotropic lattice QCD gauge field configurations with $N_{\mathrm{f}} = 2+1$ flavors of dynamical Wilson-clover fermions at…
The coupled processes -- the pion-pion scattering and pi pi --> K antiK in the I^GJ^{PC}=0^+0^{++} channel -- are analyzed (both separately and combined) in a model-independent approach based on analyticity and unitarity and using a…
We use 2HEX smeared gauge configurations generated with an $\mathrm{N}_\mathrm{f}\mathrm{=2+1}$ clover improved Wilson action to investigate $\pi\pi$ scattering in the $\rho$ channel. The range of lattice spacings (0.054 to 0.12 fm) and…
Threshold expansions of the $\pi\pi$ and $K\overline{K}$ spin 0 and isospin 0 scattering amplitudes are performed. Scattering lengths, effective ranges and so--called volume parameters are evaluated. Good agreement with the existing…
The $S$-wave $\pi K$ scattering lengths are calculated for both the isospin 1/2 and 3/2 channels in the lattice QCD by using the finite size formula. We perform the calculation with $N_f=2+1$ gauge configurations generated on $32^3 \times…
We present a new model independent amplitude analysis of reaction pi(-)p->pi(-) pi(+)n measured at CERN at 17.2 GeV/c on polarized target using a Monte Carlo method for dipion mass 580-1080 MeV. The two solutions for measured moduli…