Fermions in five-dimensional brane world models

In the present paper the fermion fields, living in the background of five-dimensional warped brane world models with compact extra dimension, are thoroughly examined. the kaluza-klein decomposition and isolation of the physical degrees of freedom is performed for those five-dimensional fermion field lagrangians, which admit such a decomposition to be performed in a mathematically consistent way and provide a physically reasonable four-dimensional effective theory. it is also shown that for the majority of five-dimensional fermion field lagrangians there are no (at least rather obvious) ways to perform the kaluza-klein decomposition consistently. moreover, in these cases one expect the appearance of various pathologies in the four-dimensional effective theory. among the cases, for which the kaluza-klein decomposition can be performed in a mathematically consistent way, the case, which reproduces the standard model by the zero kaluza-klein modes most closely regardless of the size of the extra dimension, is examined in detail in the background of the randall-sundrum model.