Quantized relativistic flux tube

We explore the dynamics of mesons composed of spinless quarks connected by a straight flux tube. The mesons are quantized and the constituent motion is relativistic. The methods developed are applied to mesons containing equal mass quarks and heavy-light quarks. For massless quarks a nearly straight leading Regge trajectory with Nambu slope is accompanied by nearly parallel equally spaced daughter trajectories. For heavy-light mesons an analogous structure is found but with double the usual Nambu slope. Comparison with six observed spin-averaged heavy-light meson states yields good agreement.