Related papers: Coarse graining $\pi\pi$ scattering
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…
In this study, we analyze the first measurement of the electron-positron invariant mass spectrum in $J/\psi \to \pi^0 e^+e^-$ by BESIII, using the framework of resonance chiral theory. Our results indicate that both strong interaction and…
We present realistic models of pion-exchange three-nucleon interactions obtained by fitting the energies of all the 17 bound or narrow states of 3 <= A <= 8 nucleons, calculated with less than 2% error using the Green's function Monte Carlo…
We present the first lattice study of pion-pion scattering with varying number of colors, $N_\text{c}$. We use lattice simulations with four degenerate quark flavors, $N_\text{f}=4$, and $N_\text{c}=3-6$. We focus on two scattering channels…
A simultaneous analysis (in the model-independent approach) of the $\pi\pi$ scattering (from the threshold to 1.9 GeV) and of the $\pi\pi\to K\overline{K}$ process (from the threshold to $\sim$ 1.46 GeV) is carried out in channel with…
I discuss recent progress in our understanding of the pi pi scattering amplitude at low energy thanks to the combined use of chiral perturbation theory and dispersion relations. I also comment on the criticism raised by Pelaez and Yndurain…
We propose a novel strategy to fit experimental data using a UV complete amplitude ansatz satisfying the constraints of Analyticity, Crossing, and Unitarity. We focus on $\pi\pi$ scattering combining both experimental and lattice data. The…
We present results from a comprehensive partial-wave analysis of pi+-p elastic scattering and charge-exchange data, covering the region from threshold to 2.6 GeV in the lab pion kinetic energy, employing a coupled-channel formalism to…
We first show that the pions produced at high $p_T$ in heavy-ion collisions over a wide range of high energies exhibit a scaling behavior when the distributions are plotted in terms of a scaling variable. We then use the recombination model…
The pion-polarizability functions are structure functions of pion-Compton scattering. They can be assessed in high-energy pion-nucleus bremsstrahlung reactions, $\pi^- +A\to\pi^- +\gamma +A$. We present numerical expectations for…
In the context of chiral SU(2) perturbation theory, pion-kaon scattering is analysed near the threshold to fourth chiral order. The scattering amplitude is calculated both in the relativistic framework and by using an approach similar to…
Phase shifts for $s$-wave $\pi\pi$ scattering in both the $I=0$ and $I=2$ channels are determined from a lattice QCD calculation performed on 741 gauge configurations obeying G-parity boundary conditions with a physical pion mass and…
The leading-particle effect and the factorization property of the scattering amplitude in the impact parameter space are used to study semiclassical production of pions in the central region. The mechanism is related to the isospin-uniform…
We report the first lattice QCD results of the scattering amplitudes of the $K\pi$ system for $I = 1/2$ channel together with $I=3/2$ case. We investigate all quark diagrams contributing to these iso-spin states, and find that the…
We calculate the two-pion wave function in the ground state of the I=2 $S$-wave system and find the interaction range between two pions, which allows us to examine the validity of the necessary condition for the finite-volume method for the…
The s-wave isoscalar amplitude for pion-pion scattering in a nuclear medium is evaluated using a nonperturbative unitary coupled channels method and the standard chiral Lagrangians. The method has proved successful to describe the pion-pion…
The COMPASS collaboration at CERN has investigated the \pi^- \gamma -> \pi^- \pi^- \pi^+ reaction at center-of-momentum energy below five pion masses, sqrt(s) < 5 m(\pi), embedded in the Primakoff reaction of 190 GeV pions impinging on a…
We evaluate analytically the elastic $\pi\pi$ scattering amplitude to two loops in chiral perturbation theory and give numerical values for the two $S$--wave scattering lengths and for the phase shift difference $\delta_0^0-\delta_1^1$.
We show that a suitable setting for comparison of the low-energy representation for pion-pion scattering amplitudes, with dispersive representation for these amplitudes, is provided by certain manifestly crossing symmetric dispersion…
A simple $\pi \pi$, $\bar{K}K$, and $\rho \rho$($\omega \omega$) fully coupled channel model is proposed to predict the isoscalar S-wave phase shifts and inelasticities for $\pi \pi$ scattering in the 1.0 to 2.0 GeV region. The S-matrix is…