Interpreting the $X(5568)$

TL;DR

This paper evaluates various theoretical models for the $X(5568)$ particle observed by D ext{O} and finds most common interpretations unlikely, proposing experimental tests to clarify its nature.

Contribution

It systematically assesses multiple models for $X(5568)$ and suggests experimental tests to determine its true nature.

Findings

Threshold, cusp, molecular, and tetraquark models are unfavored.

Proposes specific experimental tests to distinguish among remaining hypotheses.

Abstract

A variety of options for interpreting the D\O{} state, $X(5568)$, are examined. We find that threshold, cusp, molecular, and tetraquark models are all unfavoured. Several experimental tests for unravelling the nature of the signal are suggested.