Structure analysis of the generalized correlator of quark and gluon for a spin-1/2 target

We analyze the structure of generalized off-diagonal and transverse-momentum dependent quark-quark and gluon-gluon correlators for a spin-1/2 hadron. Using the lightfront formalism, we provide a parametrization in terms of the parton generalized transverse momentum dependent distributions that emphasizes the multipole structure of the correlator. The results for the quark-quark correlation functions are consistent with an alternative
parametrization given in terms of Lorentz covariant structures. The parametrization for the gluon-gluon generalized correlator is presented for the first time and allows one to introduce new correlation functions which can be relevant for phenomenological applications.