Related papers: Amplitudes Fitted to Experimental Data and to Roy'…
Utilizing the data set corresponding to an integrated luminosity of $3.19$ fb$^{-1}$ collected by the BESIII detector at a center-of-mass energy of 4.178 GeV, we perform an amplitude analysis of the $D_s^+\to\pi^+\pi^-\pi^+$ decay. The…
We study the in-medium modification of the isovector pi N amplitude using a non-linear representation of the sigma model but keeping the scalar degree of freedom. We check that our result does not depend on the representation. We discuss…
The exact joint multifractal distribution for the scaling and winding of the electrostatic potential lines near any conformally invariant scaling curve is derived in two dimensions. Its spectrum f(alpha,lambda) gives the Hausdorff dimension…
We examine the role of the elementary isoscalar pion--nucleon scattering amplitude in the description of the processes $pp \to pp\pi^0$ and $pp\to d\pi^+$ at threshold. We argue that the presently used tree level dimension two approximation…
The analysis of the vector isoscalar excitations in the energy range between 1 and 2 GeV of the $e^+e^-$ annihilation is presented for the final states $\pi^+\pi^-\pi^0$, $\omega\pi^+\pi^-$, $K^+K^-$, $K^0_SK^\pm\pi^\mp$ and…
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…
A new approach to the analysis of three body decays is presented. Measurements of the S-wave K pi amplitude are made in independent ranges of invariant mass from threshold up to the upper kinematic limit in D+ to K-pi+pi+ decays. These are…
Motivated by the results of two-dimensional conformal field theory (CFT) we investigate the finite-size scaling of the mass spectrum of an Ising model on three-dimensional lattices with a spherical cross section. Using a cluster-update…
We study forward and backward pi-pi scattering within a QCD model based on the Dyson--Schwinger, Bethe--Salpeter equations truncated to the rainbow-ladder level. Our microscopic relativistic quark formulation preserves chiral symmetry and…
The low-energy S-wave component of the decay $D^+ \to K^- \pi^+ \pi^+$ is studied by means of a chiral SU(3)XSU(3) effective theory. As far as the primary vertex is concerned, we allow for the possibility of either direct production of…
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…
It is shown that the linear correlation relates the S-wave phase shifts from the threshold up to dipion mass 900 MeV. By using this correlation at the solution of the Roy equations, the accuracy of determination of S-wave lengths is…
We consider the $\pi\pi$ scattering amplitude obtained by Colangelo, Gasser and Leutwyler (CGL), using dispersion relations and chiral perturbation theory to two loops. We point out that the input used by CGL for energies above 1.42 GeV is…
We compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial wave analysis, applied to the photoproduction of pseudo-scalar mesons. The approach is pedagogical, showing in detail how the amplitude…
As a necessary preliminary step toward geophysically significant extrapolations, we study the scale effects in internal wave attractors in the linear and nonlinear regimes. We use two geometrically similar experimental set-ups, scaled to…
We extend a recent calculation of the momentum dependence of the $\rho-\omega$ mixing amplitude to the pseudoscalar sector. The $\pi\!-\!\eta$ mixing amplitude is calculated in a hadronic model where the mixing is driven by the…
Feynman amplitudes in perturbation theory form the basis for most predictions in particle collider experiments. The mathematical quantities which occur as amplitudes include values of the Riemann zeta function and relate to fundamental…
In this paper we perform an amplitude analysis of essentially all published pion and kaon pair production data from two photon collisions below 1.5 GeV. This includes all the high statistics results from Belle, as well as older data from…
Relations between scattering and production amplitudes are studied in a microscopic multichannel model for meson-meson scattering, with coupling to confined quark-antiquark channels. Overlapping resonances and a proper threshold behaviour…
Suggested by Au, Morgan, Pennington (AMP) S-wave isospin I=0 $\pi\pi$, $KK$ scattering amplitude is good enough to describe experimental data for the moment. Still it has two disadvantages for use in multiparticle partial wave analysis…