$NJ/\psi$ and $N\eta_c$ interactions from lattice QCD

TL;DR

This study uses lattice QCD simulations to investigate the interactions between nucleons and charmonia, revealing attractive forces with specific scattering lengths, which enhances understanding of nonperturbative QCD phenomena and exotic hadron states.

Contribution

First lattice QCD calculation of nucleon-charmonium interactions near physical pion mass, providing detailed insights into their attractive nature and long-range behavior.

Findings

Interactions are attractive at all distances.

Long-range tail consistent with two-pion exchange.

Scattering lengths around 0.2 to 0.4 fm.

Abstract

The interaction between nucleon and charmonia ($J/\psi$ and $\eta_c$) is expected to deepen our understanding of various aspects in nonperturbative QCD ranging from the origin of nucleon mass to $J/\psi$ mass modification in nuclear medium and properties of hidden-charm pentaquark states. Here, we present the low-energy $NJ/\psi$ and $N\eta_c$ interactions based on ($2+1$) flavor lattice QCD simulations with nearly physical pion mass $m_\pi=146$ MeV. The interactions, extracted from the spacetime correlations of the nucleon and charmonium system by using the HAL QCD method, are found to be attractive in all distances and manifest a characteristic long-range tail consistent with the two-pion exchange interaction. The resulting scattering lengths are around $0.3$ fm, $0.4$ fm and $0.2$ fm for $NJ/\psi$ with spin $3/2$, with spin $1/2$, and $N\eta_c$, respectively. Our results are orders of magnitude larger than those from the photoproduction experiments assuming the vector meson dominance.