Four quark states in additive potentials

Masses of doubly heavy tetraquarks TQQ′ in a relativized quark model

“…Before the observation of Ξ þþ cc , there have been a number of theoretical works on the doubly heavy tetraquarks. Various approaches, involving quark models [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], QCD sum rules [43][44][45][46], and lattice QCD [47][48][49][50], were adopted to estimate their mass spectra. Due to the lack of experimental information on the doubly heavy systems, it is difficult to distinguish those numerous results.…”

udb¯b¯ tetraquark resonances with lattice QCD potentials and the Born-Oppenheimer approximation

“…Our main motivation is to investigate tetraquarks by combining lattice QCD and quantum mechanics techniques. We specialize in systems with two heavy antiquarks, which are expected to form bound states, when sufficiently heavy [5][6][7][8][9][10][11][12][13][14][15]. The starting point are potentials of two static antiquarks in the presence of two light quarks, which can be computed with state of the art lattice QCD techniques (cf.…”

Evidence for the existence ofudb¯b¯and the nonexistence ofBicudo1, Cichy2, Peters3 et al. 2015Phys. Rev. D

“…We avoid some of the technical difficulties of studying tetraquarks following a strategy already identified in the eighties [15]. We search for bound states rather than for resonances, to avoid open decay channels.…”