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

The one and two-particle form factors of the energy operator in the two-dimensional Ising model in a magnetic field at $T=T_c$ are exactly computed within the form factor bootstrap approach. Together with the matrix elements of the magnetisation operator already computed in Nucl.Phys.B455:724-758,1995, they are used to write down the large distance expansion for the correlators of the two relevant fields of the model.