Searching for hidden-charm baryonium signals in QCD sum rules

TL;DR

This paper uses QCD sum rules to investigate hidden-charm baryonium states with various quantum numbers, estimating their masses around 5.0 GeV and proposing experimental channels for their detection.

Contribution

It systematically constructs interpolating currents for hidden-charm baryonium states and evaluates their masses, providing theoretical predictions and search strategies.

Findings

Masses of hidden-charm baryonium states around 5.0 GeV

Identification of currents coupling to these states

Suggested experimental channels for detection

Abstract

We give an explicit QCD sum rule investigation to hidden-charm baryonium states with the quark content $u\bar u d\bar d c\bar c$, spin $J=0/1/2/3$, and of both positive and negative parities. We systematically construct the relevant local hidden-charm baryonium interpolating currents, which can actually couple to various structures, including hidden-charm baryonium states, charmonium states plus two pions, and hidden-charm tetraquark states plus one pion, etc. We do not know which structure these currents couple to at the beginning, but after sum rule analyses we can obtain some information. We find some of them can couple to hidden-charm baryonium states, using which we evaluate the masses of the lowest-lying hidden-charm baryonium states with quantum numbers $J^P=2^-/3^-/0^+/1^+/2^+$ to be around 5.0 GeV. We suggest to search for hidden-charm baryonium states, especially the one of $J=3^-$, in the $D$-wave $J/\psi \pi \pi$ and $P$-wave $J/\psi \rho$ and $J/\psi \omega$ channels in this energy region.