Decay Pattern of High-Spin Resonances in the Generalized Veneziano Model

The generalized Veneziano model in its factorized form allows in principle the calculation of all widths of resonances in terms of two parameters, namely (i) the coupling constant $g$ determining the over-all normalization, and (ii) the intercept ${\alpha }_0$ related to the meson mass $m ({\alpha }_0=-m^2)$. By explicitly evaluating and summing partial widths of resonances on the parent and some high-lying daughter trajectories, we have demonstrated that heavy narrow resonances exist in the model. The total widths of these resonances are found to decrease slowly as one moves to higher masses along a trajectory. For example, if one normalizes the width of the spin-1 particle on the parent trajectory to 100 MeV ($\rho$ meson), the total width at spin-9 (mass ∼3 GeV) is found to be 24 MeV, which corresponds well to missing-mass spectrometer results. A detailed study of the decay patterns of these resonances shows that the main mode of decay is one of cascade, where the resonance loses a few units of angular momentum and emits a meson at every step. To help experimenters plan future experiments, the numerical values for the widths of all important decay modes are presented. In addition, our investigation suggests that narrow high-spin resonances have a low formation cross section and are best produced in reactions with several particles in the final state.