Speaker
Description
Nucleon gravitational form factors are defined through the nucleon matrix element of the energy-momentum tensor and characterize the energy, pressure, and shear forces inside the nucleon. In particular, the gravitational form factor $D(t)$, which is associated with the spatial components of the energy-momentum tensor matrix element, plays an important role in describing the internal stress distribution and mechanical stability of the nucleon. In this work, we investigate the possibility that quarkonium–nucleon femtoscopy can serve as a new probe of nucleon gravitational form factors. The quarkonium–nucleon interaction is described by an effective potential based on the QCD multipole expansion, which relates the potential to the energy and pressure distributions inside the nucleon. The nucleon gravitational form factors are constructed using lattice-QCD data, and the remaining model parameters are fixed to be consistent with the ($J/\psi$)–nucleon potential and scattering phase shift obtained from HAL QCD. Within this framework, we calculate the ($J/\psi$)–nucleon and ($\psi(2S)$)–nucleon correlation functions and analyze their response to the D-term, $D_0=D(t=0)$. We discuss how quarkonium–nucleon femtoscopy may provide a complementary approach to exploring the mechanical structure of the nucleon from a perspective different from conventional deeply virtual processes and near-threshold quarkonium production.