Continuation of the dual amplitude with Mandelstam analyticity off mass shell

The off mass shell continuation of dual amplitude with Mandelstam analyticity (DAMA) is proposed. The modified DAMA (M-DAMA) preserves all the attractive properties of DAMA, such as its pole structure and Regge asymptotics, and leads to a generalized dual amplitude A(s,t,Q^2). In such a way we complete a unified "two-dimensionally dual" picture of strong interaction. This generalized amplitude can be checked in the known kinematical limits, i.e. it should reduce to the ordinary dual amplitude on mass shell, and to the nuclear structure function when t=0. We fix the Q^2-dependence in M-DAMA by comparing the structure function F_2, resulting from it, with phenomenological parameterizations. The results of M-DAMA are in qualitative agreement with the experiment in all studied regions, i.e. in the large and low x limits as well as in the resonance region.