Heavy and light spectroscopy near the physical point, Part II: Tetraquarks

Having introduced the ensembles and basic spectrum in Part I of this conference contribution, we focus on results for a doubly heavy tetraquark candidate, $qq^\prime \bar Q \bar Q$. Based on phenomenological observations regarding heavy baryon systems, we motivate two possible lattice interpolating operators: a diquark-antidiquark and a meson-meson. We show that these operators exhibit good behaviour both in terms of lattice QCD and their phenomenological interpretation. In particular we study the $ud \bar b \bar b$ and $\ell s \bar b \bar b$ flavor combinations and analyze their binding. At the physical point, at finite lattice spacing, we find strong indications for binding of these tetraquark candidates. We comment on possible finite volume effects and search windows for experimental confirmation.