相关论文: P_11 Resonance Extracted from pi-N Data and Its St…
We explain how an analytic continuation we have developed recently is applied to determine the residues of the nucleon resonance poles within a dynamical coupled-channel model of meson-baron reactions. A procedure for evaluating the…
The Roper resonance is described in a chiral version of the chromodielectric model as a cluster of three quarks in radial-orbital configuration (1s)$^2$(2s)$^1$, surrounded by $\pi$ and $\sigma$-meson clouds and by a chromodielectric field…
We study the electromagnetic transitions of the Roper N(1440) resonance. Our results, when combined with the previously obtained for the mass and the pionic strong decay widths of the Roper, show that within a non-relativistic constituent…
We present the results of energy-dependent and single-energy partial-wave analyses of $\pi$N elastic scattering data with laboratory kinetic energies below 2.1~GeV. Resonance structures have been extracted using Breit-Wigner fits, speed…
An existing single resonance model with S11, P11 and P13 Breit-Wiegner resonances in the s-channel has been re-applied to the old pi N --> K Lambda data. It has been shown that the standard set of resonant parameters fails to reproduce the…
A production representation of partial-wave $S$ matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated…
The properties of the Roper resonance N(1440) are reviewed. Quark models have long struggled to reproduce its mass relative to its negative-parity partner N(1535). This discrepancy motivated interpretations of the Roper as a dynamically…
The nucleon resonances are investigated within a dynamical coupled-channels model of pi N and gamma N reactions up to the invariant mass W = 2 GeV. The meson-baryon (MB) channels included in the calculations are MB = pi N, eta N, K Lambda,…
We study the stability of coupled impedance passive regular linear systems under power-preserving interconnections. We present new conditions for strong, exponential, and non-uniform stability of the closed-loop system. We apply the…
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 investigate the formation of resonances in the P33 partial wave with the emphasis on possible emergence of dynamically generated quasi-bound states as a consequence of a strong $p$-wave pion attractive interaction in this partial wave,…
Within the model of partial chemical equilibrium (PCE) we calculate the multiplicity ratios of selected unstable resonances to given stable species. We focus on those ratios that have been measured either in Pb+Pb collisions at the LHC or…
We present a lattice QCD study of $N\pi$ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in experiment. The study is based on the PACS-CS ensemble of gauge configurations with…
We compare the strong part of the $\bar{\hbox{N}}\hbox{N}$ interaction obtained by the Nijmegen partial wave analysis and the results of some of the most popular $\bar{\hbox{N}}\hbox{N}$ optical potentials in configuration space. We have…
We extend the 1/N_c meson-baryon scattering formalism to pi N to multi-pi N case. We first show that the leading-order large N_c processes proceed through resonant intermediate states (e.g., rho N or pi Delta). We find that the pole…
We calculate the decays of baryon resonances to the pion + Roper resonance channel in the frame of the flux-tube breaking model. The baryon and meson wavefunctions we use are obtained from a linear confinement semi-relativistic constituent…
We explain the application of a recently developed analytic continuation method to extract the electromagnetic transition form factors for the nucleon resonances ($N^*$) within a dynamical coupled-channel model of meson-baryon…
We show that the N(1440) Roper resonance naturally appears in the nuclear model with explicit mesons as a structure in the continuum spectrum of the physical proton which in this calculation is made of a bare nucleon dressed with a pion…
We present a pedagogical study of the commonly employed Speed-Plot (SP) and Time-delay (TD) methods for extracting the resonance parameters from the data of two particle coupled-channels reactions. Within several exactly solvable models, it…
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…