Roper resonances in chiral quark models

Abstract

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 P11 and P33 resonances. A good agreement with experimental data is achieved if in addition to the elastic channel we include the $\pi \Delta$ and $\sigma N$ ($\sigma \Delta$) channels where the $\sigma$-meson models the correlated two-pion decay. We solve the integral equation for the K matrix in the approximation of separable kernels; it yields a sizable increase of the widths of the $\Delta (1232)$ and the N(1440) resonances compared to the bare quark values.

17 pages, 7 figures

References in corpus (3)

• Dynamical coupled-channel model of meson production reactions in the nucleon resonance region
• Dynamical Coupled-Channel Model of $\pi N$ Scattering in the W $\le$ 2 GeV Nucleon Resonance Region
• The role of $qqqq\bar{q}$ components in the nucleon and the N(1440) resonance