Origin of hadron mass from gravitational D-form factor and neutron star measurements

Abstract

Clarifying the origin of hadron mass is one of the fundamental problems in particle physics, relevant from hadronic scales to astrophysical observations. At low energies, this issue is reflected in the decomposition of the hadron mass into chiral-variant and -invariant components. In this letter, we propose a method to extract the chiral invariant mass from the gravitational $D$-form factor under the assumption of the lightest-sigma meson dominance. Focusing on the nucleon, we show that a sizable chiral invariant mass is required to reproduce lattice QCD data, consistent with neutron star constraints.

Figures (3)

• Figure 1: Feynman diagrams for the nucleon GFFs. The first contribution arises from the contact interaction $NN\Theta^{\mu\nu}$ and the second is derived by the Yukawa interaction $NN\sigma$ mediated by the lightest-sigma meson.
• Figure 2: Momentum transfer dependence of $D$-form factor in the chiral framework with only the positive-parity nucleon, compared with the lattice QCD data Hackett:2023rif.
• Figure 3: Reduction of the nucleon $D$-form factor due to the chiral invariant mass, compared with the lattice QCD data Hackett:2023rif.