Baryon masses at O(a²) in chiral perturbation theory

The chiral Lagrangian for the Symanzik action through O(a^2) for baryons is obtained. We consider two flavor unquenched and partially quenched lattice theories, allowing for mixed actions in the latter. As an application, we calculate masses to O(a^2) for the nucleons and deltas, and investigate the corrections due to the violation of O(4) rotational invariance. These results are contrasted with those in the meson sector for lattice simulations using mixed and unmixed actions of Wilson and Ginsparg-Wilson quarks.