Spin-1 charmonium-like states in QCD sum rule

TL;DR

This paper uses QCD sum rules to investigate spin-1 charmonium-like tetraquark states, estimating their masses and suggesting possible interpretations for observed exotic mesons.

Contribution

It provides mass predictions for various spin-1 tetraquark states with different quantum numbers using QCD sum rules, offering insights into their possible experimental counterparts.

Findings

Mass of $1^{--}$ $qcar qar c$ state is 4.6-4.7 GeV, possibly related to Y(4660).

Masses for $1^{++}$ $qcar qar c$ and $scar sar c$ states are 4.0-4.2 GeV, near X(3872).

Masses for $1^{-+}$ and $1^{+-}$ states are 4.5-4.7 GeV and 4.0-4.2 GeV respectively.

Abstract

We study the possible spin-1 charmonium-like states by using QCD sum rule approach. We calculate the two-point correlation functions for all the local form tetraquark interpolating currents with $J^{PC}=1^{--}, 1^{-+}, 1^{++}$ and $1^{+-}$ and extract the masses of the tetraquark charmonium-like states. The mass of the $1^{--}$ $qc\bar q\bar c$ state is $4.6\sim4.7$ GeV, which implies a possible tetraquark interpretation for Y(4660) meson. The masses for both the $1^{++}$ $qc\bar q\bar c$ and $sc\bar s\bar c$ states are $4.0\sim 4.2$ GeV, which is slightly above the mass of X(3872). For the $1^{-+}$ and $1^{+-}$ $qc\bar q\bar c$ states, the extracted masses are $4.5\sim4.7$ GeV and $4.0\sim 4.2$ GeV respectively.