The X(3872) tetraquarks in B and B_s decays

TL;DR

This paper analyzes recent experimental data on the X(3872) particle in B and B_s decays, supporting its interpretation as a tetraquark state through decay patterns and mixing mechanisms, and predicts new decay channels.

Contribution

It introduces a mixing model of two quasi-degenerate states to explain decay patterns and isospin violations, providing a new prediction for J/psi omega decay modes.

Findings

Decay patterns support the tetraquark interpretation.

Charged partners likely have very small branching fractions.

Predicted decay into J/psi omega states.

Abstract

We discuss how the latest data on X(3872) in B and B_s decays speak about its tetraquark nature. The established decay pattern, including the up to date observations by CMS, are explained by the mixing of two quasi-degenerate, unresolvable, neutral states. The same mechanism also explains isospin violations in X decays and strongly suggests that the lurking charged partners are required to have very small branching fractions in J/psi rho^pm, well below the current experimental limits. In addition, a new prediction on the decay into J/psi omega final states is attained. The newest experimental observations are found to give thrust to the simplest tetraquark picture and call for a definitive, in-depth study of final states with charged rho mesons.