Renormalised pi NN Coupling Constant and the P-Wave Phase Shifts in the Cloudy Bag Model

摘要

Most applications of the cloudy bag model to pi N scattering involve unitarising the bare diagrams arising from the Lagrangian by iterating in a Lippmann-Schwinger equation. However analyses of the renormalisation of the coupling constant proceed by iterating the Lagrangian to a given order in the bare coupling constant. These two different approaches mean there is an inconsistency between the calculation of phase shifts and the calculation of renormalisation. A remedy to this problem is presented that has the added advantage of improving the fit to the phase shifts in the P sub 11 channel. This is achieved by using physical values of the coupling constant in the crossed diagram which reduces the repulsion rather than adds attraction. This approach can be justified by examining equations for the pi pi N system that incorporate three-body unitarity. (Atomindex citation 17:071279)