Finite-energy QCD sum rules

Finite-energy QCD sum rules are derived, using the operator product expansion of the two-point correlation function at complex and spacelike values of the energy, and it is also derived the experimental information on the spectral function along a limited energy range. The usual Laplace (Borel) sum rules are recovered in the limiting case in which the spectral function is assumed to be known along the whole timelike axis. In this framework the values of the quark and gluon condensates in the case of the rho current contribution of the polarization function are discussed