Exploring possibly existing $q q \bar b \bar b$ tetraquark states with $q q = ud, ss, cc$

Abstract

We compute potentials of two static antiquarks in the presence of two quarks $qq$ of finite mass using lattice QCD. In a second step we solve the Schr\"odinger equation, to determine, whether the resulting potentials are sufficiently attractive to host a bound state, which would indicate the existence of a stable $q q \bar b \bar b$ tetraquark. We find a bound state for $qq=(ud-du)/\sqrt{2}$ with corresponding quantum numbers $I(J^ P)=0(1^+)$ and evidence against the existence of bound states with isospin $I=1$ or $qq \in \{cc,ss \}$