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

TL;DR

This paper develops a dispersive formalism to calculate Regge trajectories from resonance pole data, revealing that the K0*(800) meson has a non-linear, non-ordinary trajectory, unlike typical q̄q mesons.

Contribution

It introduces a method to derive Regge trajectories from pole positions and couplings, providing evidence for the non-ordinary nature of the K0*(800) meson.

Findings

K*(892), K1(1400), K*_0(1430) have linear Regge trajectories

K0*(800) exhibits a non-linear, small-slope trajectory

Supports K0*(800) as a non-ordinary meson

Abstract

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.