Jun 13 – 17, 2011
Europe/Berlin timezone
Proceedings are now available online at <a href="http://www.slac.stanford.edu/econf/C110613/">eConf</a>

Pion scattering and electro-production on nucleons in the resonance region in chiral quark models

Jun 16, 2011, 2:30 PM
Club 1 (Künstlerhaus)

Club 1


talk Light Baryons Light Baryons


Mr Simon Sirca (Faculty of Mathematics and Physics, University of Ljubljana)


We present a method to calculate pion scattering and electro-production amplitudes in a coupled-channel framework incorporating quasi-bound quark-model states. All relevant low-lying nucleon resonances in the P33, P11, and S11 partial waves have been covered, including the Delta(1232), the N*(1440) and, most recently, the negative-parity resonances N*(1535) and N*(1650). The strong and electro-magnetic vertices of resonances are computed in the chosen quark model and not fitted. We show that even in a model as simple as the Cloudy Bag, a consistent description of the amplitudes can be achieved by using the same parameter set for all resonances. The meson cloud has been shown to play a major role, in particular in electro-magnetic observables for resonances in the P33 and P11 channels. However, the meson cloud is not strong enough to support quasi-bound states of baryons and mesons, as is the case in some models of N*(1440) and N*(1535). Consistent results were also obtained for the inelastic processes (two-pion, eta-N, and K-Lambda channels).

Primary author

Mr Simon Sirca (Faculty of Mathematics and Physics, University of Ljubljana)


Bojan Golli (Faculty of Education, University of Ljubljana)

Presentation materials