Dispersive calculation of complex Regge trajectories for the lightest $f_2$ resonances

Understand

We apply a recently developed dispersive formalism to calculate the Regge trajectories of the $f_2(1270)$ and $f_2'(1525)$ mesons.

• Trajectories are calculated, not fitted to a family of resonances.
• Assuming that these spin-2 resonances can be treated in the elastic approximation the only input are the pole position and residue of the resonances.
• In both cases, the predicted Regge trajectories are almost real and linear, with slopes in agreement with the universal value of order 1 GeV$^{-2}$.