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 q4. We show how the heat-kernel method must be extended for operators orthogonal to the heavy fermion four-velocity. We develop a method of treating 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.