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

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 c c are also discussed.