Ambiversion of X(3872)

TL;DR

This paper analyzes the X(3872) particle using recent Belle data and coupled channel models, revealing two poles near the D0D*0 threshold that suggest a mixed charmonium-molecular nature.

Contribution

It identifies a third pole near the D0D*0 threshold and proposes a dual nature of X(3872) as both a charmonium state and a molecular state, advancing understanding of its structure.

Findings

Discovery of a third pole below D0D*0 threshold

Evidence for dual charmonium-molecular nature of X(3872)

Implication of coupled channel effects on X(3872) structure

Abstract

An analysis including most recent Belle data on X(3872) is performed, using coupled channel Flatt\'e formula. A third sheet pole close to but \textit{below} $D^0D^{*0}$ threshold is found, besides the bound state/virtual state pole discussed in previous literature. The co-existence of two poles near the $D^0D^{*0}$ threshold indicates that the X(3872) may be of ordinary $c\bar c$ $2 ^3P_1$ state origin, distorted by strong coupled channel effects. The latter manifests itself as a molecular bound state (or a virtual state).