RADIALLY EXCITED BARYONS IN THE MIT BAG MODEL

We investigate radially excited baryon states in the cavity approximation to the MIT bag, with particular reference to the phenomenology of NP11 states. We show that, contrary to earlier surmìse, exchange gluon contributions to the energy are important. The model predicts NP11 states at 1525 and 1631 MeV in fair agreement with πN phase-shift analyses, both states having nonvanishing photoproduction matrix elements. We also examine the coupling of breathing modes of the bag and conclude that their effect is small on phenomenological grounds. © 1979 The American Physical Society.