Dispersive calculation of complex Regge trajectories for the lightest f2 resonances and the K⁎(892)

We apply a recently developed dispersive formalism to calculate the Regge trajectories of the f2(1270), f2′(1525) and K⁎(892) mesons. Trajectories are calculated, not fitted to a family of resonances. Assuming that these resonances can be treated in the elastic approximation, the only input are the pole position and residue of a resonance. In all three cases, the predicted Regge trajectories are almost real and linear, with slopes in agreement with the universal value of order 1 GeV−2. We also show how these results barely change when considering more than two subtractions in the dispersive formalism.