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Calculation of Regge trajectories of strange resonances and identification of the K0*(800) as a non-ordinary meson

We review how the Regge trajectory of an elastic resonance can be obtained just from its pole position and coupling, using a dispersive formalism. This allows us to deal correctly with the finite widths of resonances in Regge trajectories. In this way we can calculate the Regge trajectories for the $K^*(892)$, $K_1(1400)$ and $K^*_0(1430)$, obtaining ordinary linear Regge trajectories, expected for $q \bar q$ resonances. In contrast, for the $K^*_0(800)$ meson, the resulting Regge trajectory is non-linear and with much smaller slope, strongly supporting its non-ordinary nature.