Mass spectra for the $cc\bar{b}\bar{b}$/$bb\bar{c}\bar{c}$ tetraquark states

TL;DR

This study predicts the masses of $cc\bar{b}\bar{b}$ and $bb\bar{c}\bar{c}$ tetraquark states using QCD sum rules, indicating some are below decay thresholds and may be stable and narrow.

Contribution

First systematic calculation of tetraquark masses with various quantum numbers using QCD sum rules.

Findings

Positive parity $cc\bar{b}\bar{b}$ states are around 12.3-12.4 GeV.

Negative parity states are around 12.8-13.1 GeV.

Some states are below the $B_c B_c$ threshold, suggesting potential stability.

Abstract

We have studied the masse spectra for the $cc\bar{b}\bar{b}$/$bb\bar{c}\bar{c}$ tetraquark states with quantum numbers $J^{P}=0^{\pm},1^{\pm}$, 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 $cc\bar{b}\bar{b}$ tetraquark ground states with $J^{P}=0^+, 1^+, 2^+$, while $12.8-13.1$ GeV for the negative parity channels with $J^{P}=0^-, 1^-$. The mass predictions for the positive parity $cc\bar{b}\bar{b}$ 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.