Improved analysis of strong-interaction-stable doubly-bottom tetraquarks on the lattice

TL;DR

This paper refines lattice calculations of doubly bottom tetraquark binding energies, employing improved techniques and larger volumes, providing results that aid experimental searches for these exotic states.

Contribution

The study introduces an extended sink construction and larger-volume ensembles to improve lattice QCD calculations of doubly bottom tetraquarks, updating previous binding energy results and exploring heavy mass dependence.

Findings

Binding energy for I=0 state: 115(17) MeV

Binding energy for I=1/2 state: 47(8) MeV

Heavy mass dependence of binding analyzed

Abstract

We update earlier lattice results for the binding energies of the flavor antitriplet of strong-interaction-stable doubly bottom, $J^P=1^+$ tetraquarks, employing an extended sink construction which produces significantly improved ground-state effective-mass plateaus, as well as new, larger-volume ensembles which reduce possible finite-volume effects at lighter pion masses. The updated bindings are $115(17)$ MeV for the $I=0$ member of the antitriplet and $47(8)$ MeV for its $I=1/2$ partner. We also provide an update of our earlier study of the variable heavy mass dependence of binding in the $1^+$ channel and new results on this dependence for binding in the $0^+$ channel, accessible when the two heavy quarks have unequal masses. Implications of these results of potential relevance to experimental searches for signals of the production of doubly bottom tetraquarks and/or a possible bottom-charm partner of the $T_{cc}$ are also discussed.