Existence of tetraquark states at large N_c

Determine whether tetraquark states—four‑quark configurations such as diquark–antidiquark bound states—form and persist in the large‑N_c limit of quantum chromodynamics; specifically, ascertain if any tetraquarks survive with masses scaling as N_c^0 and widths scaling as N_c^{-1}, rather than fading away as N_c increases.

Background

The paper reviews large‑N_c behavior of various hadronic bound states and shows that conventional quarkonia, glueballs, and hybrids survive with N_c‑independent masses and suppressed widths. In contrast, mesonic molecules and dynamically generated states do not form at large N_c within the authors’ bound‑state framework.

The status of compact tetraquarks at large N_c is highlighted as unresolved. Weinberg proposed that certain tetraquarks might exist at large N_c with quarkonium‑like scaling, but subsequent works offer differing views. The authors discuss heuristic arguments suggesting tetraquarks may not bind in their approach, yet explicitly note that this issue remains unclear and requires further paper.