X (3872) as a Universal and Composite State

TL;DR

This paper explores the X(3872) particle as a universal, composite state, emphasizing its molecular nature, universality, and compositeness, and discusses how physical observables relate to its structure.

Contribution

It introduces a framework to analyze X(3872) as a weakly bound molecule using universality and compositeness criteria, providing new insights into its structure.

Findings

X(3872) can be modeled as a non-relativistic weakly bound molecule.

Universal observables are insensitive to short-range interaction details.

Weinberg's compositeness criterion helps classify the particle's structure.

Abstract

X (3872) because of its mass that is just below D^0 D-^0* threshold and its quantum number j^pc=1^++ can be considered as a weakly bound molecule. It can be regarded as a non-relativistic system depicting universality and compositeness. Physical observables are called universal if they are insensitive to the range and other details of short-range interaction. Weinberg introduced compositeness criterion to classify a two-body composite system as the sum, with different weights, of a compact core and two distinct parts.