Width of a two-body coupled-channel resonance

TL;DR

This paper investigates how the width of a two-body coupled-channel resonance is influenced not just by phase space but also by the resonance's mass position relative to coupled channels, explaining narrow hadrons above decay thresholds.

Contribution

It reveals the significant dependence of resonance width on the resonance's mass position within coupled channels, extending understanding beyond phase space considerations.

Findings

Resonance width depends on mass position relative to coupled channels.

Narrow hadrons can exist well above decay thresholds.

Width is not solely determined by available phase space.

Abstract

We study the width of a two-body resonance in a coupled-channel system. We demonstrate how the width does not come only determined by the available phase space for its decay to the detection channel, but it greatly depends on the relative position of the mass of the resonance with respect to the masses of the coupled-channels generating the state. Our results are consistent with the experimental observation of narrow hadrons lying well above their lowest decay threshold.