The no-wall holographic model for vector quarkonia
  We use the no-wall holographic approach (a relative of the soft-wall one) to construct a universal description of vector mesons with arbitrary quark masses. The proposed model predicts a specific dependence of the parameters of radial Regge trajectories on the quark masses in a reasonable agreement with the meson phenomenology and some theoretical expectations. 
S. S. Afonin and I. V. Pusenkov
hep-ph