Refined lattice/model investigation of $ud\bar{b}\bar{b}$ tetraquark candidates with heavy spin effects taken into account

We investigate four-quark systems consisting of two heavy anti-bottom quarks and two light up/down quarks. We propose to solve a coupled Schr"odinger equation for the anti-bottom-anti-bottom separation using potentials computed via lattice QCD in the limit of static anti-bottom quarks. This coupled Schr"odinger equation allows to incorporate effects due to the heavy anti-bottom spins. First exploratory numerical tests are discussed.