Scalar fully-charm and bottom tetraquarks under extreme temperatures

Temperature dependences of masses and current couplings of the ground state of the fully heavy tetraquarks $T_{4c}$ and $T_{4b}$, composed of charm $(c)$ and bottom $(b)$ quarks and antiquarks with spin-parities $J^{PC} = 0^{++}$ are evaluated in the diquark antidiquark picture using Thermal QCD Sum Rules including vacuum condensates up to dimension four. The calculated values for $cc\bar{c}\bar{c}$ and $bb\bar{b}\bar{b}$ tetraquark states at $T=0$ align well with the experimental data on the broad structures. Based on the numerical analyses around the critical temperature, the mass of the $T_{4c}$ state decreases by $8\%$ compared to its vacuum state, while for its b partner, this percentage is approximately $3.3\%$. For the decay constants, the reductions are approximately $71\%$ and $66.6\%$, respectively. The precise exploration of tetraquark states awaits future scrutiny in upcoming experiments, including Belle II, Super-B, PANDA, and LHCb.