QUANTUM LIGHT-CONE DYNAMICS OF A STRING WITH MASSES AT THE ENDS

The light-cone Hamiltonian incorporating the nonperturbative dynamics of the q (q) over bar system connected by a string is solved numerical ly. The spectrum is shown to coincide with that of the center-of-mass Hamiltonian within the accuracy of computation, displaying the expecte d degeneracies of string states, but an overall shift due to different treatment of Z graphs is obtained. The nonperturbative wave functions are calculated directly from the light-cone Hamiltonian for the first time, thus allowing the explicit estimation of nonperturbative effect s in terms of the parton model. In this way, the string contributions to the parton distributions and to the form factors and structure func tions are obtained.