$b\bar b u\bar d$ four-quark systems in the Born-Oppenheimer approximation: prospects and challenges

TL;DR

This paper reviews previous research on $ar b ar b u ar d$ four-quark systems using the Born-Oppenheimer approximation and explores initial approaches to studying the more complex $bar b uar d$ system, including potential bound states.

Contribution

It extends the Born-Oppenheimer approximation framework from $ar b ar b u ar d$ to the more challenging $bar b uar d$ system, proposing strategies and presenting initial numerical results.

Findings

Discussion of strategies to identify bound states.

Initial numerical results on the $bar b uar d$ system.

Insights into the challenges of extending the approximation.

Abstract

We summarize previous work on $\bar b \bar bud$ four-quark systems in the Born-Oppenheimer approximation and discuss first steps towards an extension to the theoretically more challenging $b\bar b u\bar d$ system. Strategies to identify a possibly existing $b\bar b u\bar d$ bound state are discussed and first numerical results are presented.