Lattice QCD study of heavy-heavy-light-light tetraquark candidates
  We investigate heavy-light four-quark systems $ud\bar b \bar b$ with bottom quarks of finite mass which are treated in the framework of NRQCD. We focus on $I(J^P)=0(1^+)$, where we recently found evidence for the existence of a tetraquark state using static bottom quarks. Furthermore, we report on an investigation of the $u \bar d b \bar b$ four-quark system with quantum numbers $I(J^P)=1(1^+)$ again using static bottom quarks. 
Antje Peters, Pedro Bicudo, Luka Leskovec, Stefan Meinel, Marc Wagner
hep-lat hep-ph