Holographic tetraquarks and the newly observed $T_{cc}^{+}$ at LHCb

Abstract

We describe a heavy and exotic tetraquark state as a holographic molecule, by binding the lightest heavy-light meson $(0^{-},1^{-})$ multiplet to a flavored sphaleron, in the bulk of the Witten-Sakai-Sugimoto model. Bound tetraquark states emerge as Efimov states in the heavy quark limit, with a binding energy for charm tetraquark comparable to the $T_{cc}^{+}$ recently reported by the LHCb, but a substantially smaller width, for a large but finite ${}^{\prime }$t Hooft coupling. Fixing the parameters of the model at the empirical mass of $T_{cc}^{+}$ allows us to predict the bindings of the undiscovered so far bottom-charm and bottom tetraquarks, when interpreted as Efimov states.

Comments: 9 pages, discussion on newly discovered $T_{cc}^{+}$ added, alternative quantization of moduli as bosons added