Investigation of the stability for fully-heavy $bc\bar{b}\bar{c}$ tetraquark states

TL;DR

This paper investigates the masses and stability of fully-heavy $bcar{b}ar{c}$ tetraquark states using QCD sum rules, finding some states likely stable against strong decay and others capable of spontaneous dissociation.

Contribution

It provides the first detailed mass estimates for various $bcar{b}ar{c}$ tetraquark states and analyzes their potential stability and decay channels.

Findings

S-wave positive parity states have masses around 12.2-12.4 GeV, likely stable.

P-wave negative parity states have masses around 12.9-13.2 GeV, can decay into specific meson pairs.

Most states are below certain thresholds, indicating possible stability against strong interactions.

Abstract

We study the existence of fully-heavy hidden-flavor $bc\bar{b}\bar{c}$ tetraquark states with various $J^{PC}=0^{\pm+}, 0^{--},1^{\pm\pm}, 2^{++}$, by using the moment QCD sum rule method augmented by fundamental inequalities. Using the moment sum rule analyses, our calculation shows that the masses for the S-wave positive parity $bc\bar{b}\bar{c}$ tetraquark states are about $12.2-12.4$ GeV in both $[\mathbf{\bar{3}_c}]_{bc}\otimes[\mathbf{3_c}]_{\bar{b}\bar{c}}$ and $[\mathbf{6_c}]_{bc}\otimes[\mathbf{\bar{6}_c}]_{\bar{b}\bar{c}}$ color configuration channels. Except for two $0^{++}$ states, such results are below the thresholds $T_{\eta_c\eta_b}/T_{\Upsilon\psi}$ and $T_{B_cB_c}$, implying that these S-wave positive parity $bc\bar{b}\bar{c}$ tetraquark states are probably stable against the strong interaction. For the P-wave negative parity $bc\bar{b}\bar{c}$ tetraquarks, their masses in the $[\mathbf{\bar{3}_c}]_{bc}\otimes[\mathbf{3_c}]_{\bar{b}\bar{c}}$ channel are around $12.9-13.2$ GeV, while a bit higher in the $[\mathbf{6_c}]_{bc}\otimes[\mathbf{\bar{6}_c}]_{\bar{b}\bar{c}}$ channel. They can decay into the $c\bar c+b\bar b$ and $c\bar b+b\bar c$ final states via the spontaneous dissociation mechanism, including the $J/\psi\Upsilon$, $\eta_c\Upsilon$, $J/\psi\eta_b$, $B_c^+B_c^-$ channels.