# Lattice QCD Study of the Nucleon-Charmonium Interaction

## TL;DR

This study uses lattice QCD calculations to analyze the interaction between J/psi mesons and nucleons, identifying key spin-dependent forces and their effects on hyperfine splitting.

## Contribution

The paper introduces a quantitative determination of spin-dependent forces in J/psi-nucleon interactions using the time-dependent HAL QCD method.

## Key findings

- Spin-spin force causes hyperfine splitting.
- Tensor forces have minor effects on S-wave scattering.
- Interaction characterized by four terms: central, spin-spin, and two tensor forces.

## Abstract

The $J/\psi$-nucleon interaction is studied by lattice QCD calculations. At the leading order of the derivative expansion, the interaction consists of four terms: the central, the spin-spin, and two types of tensor forces. We determine these spin-dependent forces quantitatively by using the time-dependent HAL QCD method. We find that the spin-spin force is the main cause of the hyperfine splitting between the $J=1/2$ and the $J=3/2$ states, while the two tensor forces have much smaller effects on the S-wave scattering processes.