Renormalization of the chiral pion-nucleon Lagrangian beyond next-to-leading order

The complete renormalization of the generating functional for Green functions of quark currents between one-nucleon states in two flavor heavy baryon chiral perturbation theory is performed to order $q^4$. We show how the heat kernel method has to be extended for operators orthogonal to the heavy fermion four-velocity. A method is developed to treat the multi-coincidence limit arising from insertions of dimension two (and higher) operators on internal baryon propagators in self-energy graphs. As examples, we study the divergences in the isoscalar magnetic moment and the scalar form factor of the nucleon.