相关论文: pi-pi Scattering and the Meson Resonance Spectrum

We describe the method for extracting the elastic scattering phase shift from a lattice simulation at an introductory level, for non-lattice practitioners. We consider the scattering in a resonant channel, where the resulting phase shift…

We have performed a thorough study of the meson-meson S-waves with isospin (I) 0 and 1/2, up to sqrt(s) ~ 2 GeV. This is the first study that includes 13 channels that have their threshold below that energy. All the resonances below 2 GeV,…

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).…

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…

We present a calculation of the phase-shift for $\pi$-$\pi$ scattering in isospin-1, spin-1 channel in the elastic region. The mass and width of the rho resonance is extracted by fitting these phaseshifts. To vary the scattering momentum we…

The scalar -- isoscalar pi-pi phase shifts are analysed using a separable potential model of three coupled channels (pipi, KK and an effective 2pi2pi system). Model parameters are fitted to two sets of solutions obtained in a recent…

The $s-$wave meson-baryon scattering is analyzed for the isospin-strangeness $I=1/2, S=0$ and $I=0,S=-1$ sectors, in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. For both sectors, four channels have been…

A model for $\pi$N scattering and $\eta$-meson production in the S$_{11}$ channel is presented. The model includes $\pi$N-scattering Born terms as well as the N$^*${} resonances S$_{11}$(1535) and S$_{11}$(1610). The $T$-matrix is computed…

We study coupled channel effects upon isospin I=2 and I=0 $\pi\pi$ S-wave interaction. With introduction of the $\pi\pi\to\rho\rho\to\pi\pi$ coupled channel box diagram contribution into $\pi\pi$ amplitude in addition to $\rho$ and $f_2…

We present for the first time a determination of the energy dependence of the isoscalar $\pi\pi$ elastic scattering phase-shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are computed…

We set up a general framework to describe $\pi\pi$ scattering below 1 GeV based on chiral low-energy expansion with possible spin-0 and 1 resonances. Partial wave amplitudes are obtained with the $N/D$ method, which satisfy unitarity,…

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…

We estimate the I=0 scalar meson sigma/f_0(600) parameters from pi-pi and gamma-gamma scattering data below 700 MeV using an improved analytic K-matrix model. A fit of the hadronic data gives a complex pole mass M_sigma= 422-i290 MeV, while…

Pion-kaon ($\pi K$) pairs occur frequently as final states in heavy-particle decays. A consistent treatment of $\pi K$ scattering and production amplitudes over a wide energy range is therefore mandatory for multiple applications: in…

The Compton scattering on a charged pion and the process \gamma\gamma \to \pi^0\pi^0 are studied using the dispersion relations. Unknown parameters of the S-wave \pi\pi interaction, represented as a board Breit-Wignar resonance, and a sum…

The problem of scalar mesons still remains a challenging puzzle, for which we do not even know which are the right pieces to set up. The proliferation of resonances (some of them are very broad and appear on top of hadronic thresholds) and…

We employ a variational basis with a number of $\bar{q}q$ and $\pi\pi$ lattice interpolating fields with quantum numbers of the $\rho$ resonance to extract the discrete energy spectrum in a finite volume. In the elastic region, this…

We present the first calculation of coupled-channel meson-meson scattering in the isospin $=1$, $G$-parity negative sector, with channels $\pi \eta$, $K\overline{K}$ and $\pi \eta'$, in a first-principles approach to QCD. From the discrete…

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 underlying mixing of quark components of scalar mesons is probed in $\pi K$ scattering within a generalized linear sigma model that contains two scalar meson nonets and two pseudoscalar meson nonets (a quark-antiquark and a four-quark).…