Mass spectra for the ccb¯b¯ and bbc¯c¯ tetraquark states

Abstract

We have studied the masse spectra for the $cc\overline{b}\overline{b}$ and $bb\overline{c}\overline{c}$ tetraquark states with quantum numbers ${J}^{P}={0}^{\ifmmode\pm\else\textpm\fi{}},{1}^{\ifmmode\pm\else\textpm\fi{}}$, and ${2}^{+}$. We systematically construct the interpolating currents with various spin-parity quantum numbers and calculate their two-point correlation functions in the framework of QCD moment sum rule method. Our calculations show that the masses are about 12.3--12.4 GeV for the positive parity $cc\overline{b}\overline{b}$ tetraquark ground states with ${J}^{P}={0}^{+},{1}^{+},{2}^{+}$, while 12.8--13.1 GeV for the negative parity channels with ${J}^{P}={0}^{\ensuremath{-}},{1}^{\ensuremath{-}}$. The mass predictions for the positive parity $cc\overline{b}\overline{b}$ ground states are lower than the ${B}_{c}{B}_{c}$ threshold, implying that these tetraquarks can only decay via weak interaction and thus are expected to be stable and narrow.