The quantum properties of a helix-like shaped QCD string are studied in the context of the semi-classical Lund fragmentation model. It is... Show moreThe quantum properties of a helix-like shaped QCD string are studied in the context of the semi-classical Lund fragmentation model. It is shown how simple quantization rules combined with the causality considerations in the string fragmentation process describe the mass hierarchy of light pseudoscalar mesons. The quantized helix string model predicts observable quantum effects related to the threshold behaviour of the intrinsic transverse momentum of hadrons, and of the minimal transverse momentum difference between adjacent hadrons. Sponsorship: IIT College of Science, High Energy Physics Division of Argonne National Laboratory Show less