Lattice study on $\eta_{c2}$ and X(3872)

TL;DR

This lattice QCD study calculates the mass and decay width of the $ ext{eta}_{c2}$ charmonium state, providing insights into its properties and potential relation to the X(3872) particle.

Contribution

The paper presents the first lattice QCD determination of the $ ext{eta}_{c2}$ mass and decay width, aiding in understanding its nature and relation to the X(3872).

Findings

Mass of $ ext{eta}_{c2}$ is 3.80(3) GeV.

Transition width $ ext{eta}_{c2} o ext{J/}\psi \, ext{gamma}$ is 3.8(9) keV.

Results support the possible $2^{-+}$ assignment to X(3872).

Abstract

Properties of $2^{-+}$ charmonium $\eta_{c2}$ are investigated in quenched lattice QCD. The mass of $\eta_{c2}$ is determined to be 3.80(3) GeV, which is close to the mass of $D$-wave charmonium $\psi(3770)$ and in agreement with quark model predictions. The transition width of $\eta_{c2}\to \gamma J/\psi$ is also obtained with a value $\Gamma=3.8(9)$ keV. Since the possible $2^{-+}$ assignment to X(3872) has not been ruled out by experiments, our results help to clarify the nature of X(3872).