Evidence for the existence of $ud\bar{b}\bar{b}$ and the non-existence of $ss\bar{b}\bar{b}$ and $cc\bar{b}\bar{b}$ tetraquarks from lattice QCD

We combine lattice QCD results for the potential of two static antiquarks in the presence of two quarks $qq$ of finite mass and quark model techniques to study possibly existing $qq\bar{b}\bar{b}$ tetraquarks. While there is strong indication for a bound four-quark state for $qq=(ud-du)\mathrm{/}\sqrt{2}$, i.e. isospin $I=0$, we find clear evidence against the existence of corresponding tetraquarks with $qq\in \{uu,(ud+du)\mathrm{/}\sqrt{2},dd\}$, i.e. isospin $I=1$, $qq=ss$ and $qq=cc$.