Related papers: Coupled channel effects in pion pion S-wave intera…
A new evaluation of the universal $\pi\pi$ scattering length relation is used to extract the $\pi\pi$ $s$-wave scattering lengths from threshold pion production data. Previous work has shown that the chiral perturbation series relating…
The low-energy S-wave pi N and K N scatterings are studied by the K-matrix approach within the meson exchange framework. The t-channel meson exchanges, especially rho and sigma exchanges, are found to play a very important role in these two…
The effect of isoscalar S-wave processes $\pi\pi\to\pi\pi,K\overline{K},\eta\eta$ is considered in the analysis of data (from the ARGUS, CLEO, CUSB, Crystal Ball, Belle, BABAR collaborations) on the bottomonia decays ---…
The isospin-2 pi pi system provides a useful testing ground for determining elastic hadron scattering parameters from finite-volume spectra obtained using lattice QCD computations. A reliable determination of the excited state spectrum of…
The s-wave pion-pion ($\pi\pi$) scattering lengths are computed below the inelastic threshold by the L\"uscher technique with pion masses ranging from 240 MeV to 463 MeV. In the Asqtad-improved staggered fermion formulation, we calculate…
We perform a coupled-channel analysis of pseudodata for the D+-> K-pi+pi+ Dalitz plot. The pseudodata are generated from the isobar model of the E791 Collaboration, and are reasonably realistic. We demonstrate that it is feasible to analyze…
In order to analyze data on charged pions correlation channels, pi^+(2pi^-) and pi^-(2pi^+), we propose new interferometry approach using the Coulomb wave function. We show that to describe adequately data we have to introduce new parameter…
The results of the recent experiments on the reaction $\pi^-p\to\pi^0\pi^0n$ performed at KEK, BNL, IHEP, and CERN are analyzed in detail. For the I=0 $\pi\pi$ S wave phase shift $\delta^0_0$ and inelasticity $\eta^0_0$ a new set of data is…
We present the first determination of $\rho \pi$ scattering, incorporating dynamically-coupled partial-waves, using lattice QCD, a first-principles numerical approach to QCD. Considering the case of isospin-2 $\rho \pi$, we calculate…
This work presents a lattice quantum chromodynamics (QCD) determination of $\pi\pi\pi$ scattering amplitudes for the isospin-2 channel with angular momentum and parity $J^{P} = 1^+$. The calculation is performed using unphysically heavy…
The influence of the hadronic \pi\pi interaction on the wave functions of pionium (the Coulomb bound \pi^+\pi^- system) at distances less than 10 fm is calculated for s-states with principal quantum numbers n<5. Hadronic \pi\pi potentials…
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 a nonperturbative approach which combines coupled channel Lippmann Schwinger equations with meson-meson potentials provided by the lowest order chiral Lagrangians. By means of one parameter, a cut off in the momentum of the loop…
The NA48/2 collaboration has shown clear experimental evidence for a cusp in the data for K -> pi pi^0 pi^0. This effect can be used to extract information on the pi-pi scattering lengths. We address this issue using a two-loop dispersive…
We use a nonpertubative approach which combines coupled channel Lippmann Schwinger equations with meson-meson potentials provided by the lowest order chiral Lagrangian. By means of one parameter, a cut off in the momentum of the loop…
We report on a dispersion relation for the \gamma\gamma\to (\pi\pi)_I S-wave in isospin I emphasizing the low energy region. The f_0(980) signal that emerges in \gamma\gamma\to \pi\pi is also discussed. Our results could be used to…
The ETH model of the pion-nucleon ($\pi N$) interaction contains $t$-channel $\sigma$- and $\rho$-exchange graphs, as well as the $s$- and $u$-channel contributions with the well-established $s$ and $p$ baryon states with masses below $2$…
A joint analysis of the pi+pi- and pi0pi0 S-wave amplitudes including results of three experiments has been performed. Using our theoretical model of the pion-pion production in which not only the pion exchange but also the a1(1260) meson…
We present a study of the $\pi\pi$ scattering amplitude in the $\sigma$ and $\rho$ channels at finite temperature and nuclear density within a chiral unitary framework. Meson resonances are dynamically generated in our approach, which…
Interactions in three coupled channels: pi-pi, K-anti K and sigma-sigma have been investigated in a wide two-pion effective mass region from the pi-pi threshold up to 1600 MeV. Analytical structure of amplitudes in all channels has been…