A string model of mesons

A string-type meson model with two massive quarks is presented. It is solved exactly by means of almost periodic functions in 3 + 1 space-time dimensions. The solutions, Poincare generators, and Hamiltonian bear formal resemblance to the corresponding free string quantities. The leading (rising) Regge trajectory is linear but has negative intercept. The degeneracy of the spectrum is greatly reduced and the breaking of reparametization invariance by the non-zero quark masses requires an asymptotic application of the gauge conditions of Virasoro in order that the physical subspace of the usual Nambu string be obtained in the massless limit. Modifications necessary to construct more realistic models and their extensions to baryons are indicated. (Auth.)