Correlation functions in the two-dimensional Ising model in a magnetic field at T = Tc

The one- and two-particle form factors of the energy operator in the two-dimensional Ising model in a magnetic field at T = Tc are exactly computed within the form factor bootstrap approach. Together with the matrix elements of the magnetisation operator already computed by G. Delfino and G. Mussardo [Nucl. Phys. B 455 (1995) 724], they are used to write down the large distance expansion for the correlators of the two relevant fields of the model.