Concavity of the meson Regge trajectories

Abstract

It is illustrated by the fitted Regge trajectories for a large majority of mesons that the radial and orbital Regge trajectories for mesons prefer being concave in the (nr,M2) and (l,M2) planes, respectively. The concavity of the meson Regge trajectories is model-independent. The concavity is expected to act as a criterion to choose a newly observed meson or to assign a particle to the unwell-established state. The concavity of the meson Regge trajectories can assist in model construction and in the choice of the appropriate model to describe mesons. The appropriate models should yield the spectra which can produce the concave Regge trajectories according to the concavity of the meson Regge trajectories. If the large majority of the meson Regge trajectories are concave while a few meson Regge trajectories are convex which neither have been confirmed nor have been completely excluded at present, many existing models should be corrected or even be reconstructed, which will lead to the further understanding of the meson dynamics.