Quantum Corrections to Baryon Properties in Chiral Soliton Models

Chiral lagrangians as e ective eld theories of QCD are successfully applied to meson physics at low energies in the framework of chiral perturbation theory. Because of their nonlinear structure these lagrangians allow for static soliton solutions which may be interpreted as baryons. Their semiclassical quantization, which provides the leading order in an 1=NC expansion (NC is the number of colors) turned out to be insu cient in many cases to obtain good agreement with empirical baryon observables. However with NC = 3, large corrections are expected in the next-to-leading order which is carried by pionic uctuations around the soliton background. The calculation of these corrections requires renormalization to 1-loop of the underlying eld theory. We present a procedure to calculate the 1-loop contributions for a variety of baryonic observables. In contrast to chiral perturbation theory, terms with an arbitrary number of gradients may in principle contribute and the restriction to low chiral orders can only be justi ed by the investigation of the scale independence of the results. The results generally give the right sign and magnitude to reduce the discrepancy between theory and experiment with one exception: the axial quantities. These su er from the fact that the underlying current algebra mixes di erent NC orders, which suggests a large and positive next-to-next-to-leading order contribution, which is probably su cient to close the gap to experiment.