https://doi.org/10.1140/epja/i2008-10677-3
Regular Article - Theoretical Physics
Roper resonances in chiral quark models
1
Faculty of Education, University of Ljubljana and J. Stefan Institute, 1000, Ljubljana, Slovenia
2
Faculty of Mathematics and Physics, University of Ljubljana and J. Stefan Institute, 1000, Ljubljana, Slovenia
* e-mail: bojan.golli@ijs.si
Received:
27
May
2008
Revised:
1
October
2008
Accepted:
29
October
2008
Published online:
21
November
2008
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 
and 
N (
channels where the -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 (1232) and the N(1440) resonances compared to the bare quark values.
PACS: 11.80.Gw Multichannel scattering – / 12.39.Ba Bag model – / 14.20.Gk Baryon resonances with S = 0 –
© SIF, Springer-Verlag Berlin Heidelberg, 2008
