Eur. Phys. J. A (2025) 61: 118
https://doi.org/10.1140/epja/s10050-025-01599-1

Regular Article - Theoretical Physics

Fully heavy asymmetric scalar tetraquarks

¹ Institute for Physical Problems, Baku State University, 1148, Baku, Azerbaijan
² Department of Physics, University of Tehran, North Karegar Avenue, 14395-547, Tehran, Iran
³ Department of Physics, Dogus University, Dudullu-Ümraniye, 34775, Istanbul, Turkey
⁴ Department of Physics Engineering, Istanbul Medeniyet University, 34700, Istanbul, Turkey

^a kazem.azizi@ut.ac.ir

Received: 21 February 2025
Accepted: 14 May 2025
Published online: 24 May 2025

Abstract

The scalar tetraquarks $T_b$ and $T_c$ with asymmetric contents $bb\overline{b}\overline{c}$ and $cc\overline{c}\overline{b}$ are explored using the QCD sum rule method. These states are modeled as the diquark–antidiquarks composed of the axial-vector components. The masses and current couplings of $T_b$ and $T_c$ are calculated using the two-point sum rule approach. The predictions obtained for the masses of these four-quark mesons prove that they are unstable against the strong two-meson fall-apart decays to conventional mesons. In the case of the tetraquark $T_b$ this is the decay $T_{\text{b}}\to {\eta }_b{B}_c^{-}$. The processes $T_{\text{c}}\to {\eta }_c{B}_c^{+}$ and $J/\psi B_c^{\ast +}$ are kinematically allowed decay modes of the tetraquark $T_c$. The widths of corresponding processes are evaluated by employing the QCD three-point sum rule approach which are necessary to estimate strong couplings at the tetraquark-meson-meson vertices of interest. The mass $m=(15698\pm 95)\text{MeV}$ and width $\mathrm{\Gamma }[T_b]=(36.0\pm 10.4)\text{MeV}$ of the tetraquark $T_b$ as well as the parameters $\tilde{m}=(9680\pm 102)\text{MeV}$ and $\mathrm{\Gamma }[T_c]=(54.7\pm 12.6)\text{MeV}$ in the case of $T_c$ provide useful information to search for and interpret new exotic states.