Exotic $T_{c\bar{s}0}^a(2900{)}^0$ and $T_{c\bar{s}0}^a(2900{)}^{++}$ states in Born-Oppenheimer approximation

Abstract

We employ Born-Oppenheimer approximation to the $T_{c\bar{s}0}^a(2900{)}^0$ and $T_{c\bar{s}0}^a(2900{)}^{++}$ states observed by the LHCb Collaboration and study mass spectrum and root-mean-square radius values. For this purpose, we use dynamical diquark model. We assume that strange quark is a heavy for the usage of Born-Oppenheimer approximation. Our results strongly indicate that the $T_{c\overline{s}0}^a(2900)$ states are best described as composed of axial-vector (spin-1) diquark pairs. Furthermore, the calculated root-mean-square radius, $⟨r^2{⟩}^{1/2}\approx 0.70-0.80$ fm, which is significantly less than 1 fm, provides compelling evidence that these are compact tetraquarks rather than loosely bound hadronic molecules.

Comments: 13 pages, 7 tables, 4 figures. Excited states included and new references added