Dispersive Determination of Nucleon Gravitational Form Factors

Abstract

Being closely connected to the origin of the nucleon mass, the gravitational form factors of the nucleon have attracted significant attention in recent years. We present the first model-independent determinations of the gravitational form factors of the pion and nucleon at the physical pion mass, using a data-driven dispersive approach. The so-called "last global unknown property" of the nucleon, the $D$-term, is determined to be $-3.38_{-0.35}^{+0.34}$. The root mean square radius of the scalar trace density inside the nucleon is determined to be $(0.97\pm 0.03)\text{fm}$. Notably, this value is larger than the proton charge radius, suggesting a modern structural view of the nucleon where gluons, responsible for most of the nucleon mass, are distributed over a larger spatial region than quarks, which dominate the charge distribution, indicating that the radius of the trace density may be regarded as a confinement radius. We also predict the nucleon angular momentum and mechanical radii, providing further insights into the intricate internal structure of the nucleon.

v2: 10 pages, 6 figures, 1 table. Adopted a more conservative error analysis: minor shifts in results (central values unchanged). Expanded supplementary material: added derivations of GFF unitarity relations and input discussions. Clarifications of mass radius added, title changed, main conclusions unchanged

References in corpus (19)

• The pion-pion scattering amplitude. IV: Improved analysis with once subtracted Roy-like equations up to 1100 MeV
• Dispersion analysis of the nucleon form factors including meson continua
• Nucleon form-factors of the energy momentum tensor in the chiral quark-soliton model
• The nucleon form-factors of the energy momentum tensor in the Skyrme model
• On the pi pi continuum in the nucleon form factors and the proton radius puzzle
• Roy-Steiner equations for pion-nucleon scattering
• On LHCb pentaquarks as a baryon-psi(2S) bound state -- prediction of isospin 3/2 pentaquarks with hidden charm
• Extracting the sigma-term from low-energy pion-nucleon scattering
• Dispersive analysis of the scalar form factor of the nucleon
• Dispersive evaluation of the D-term form factor in deeply virtual Compton scattering
• Energy momentum tensor and the D-term in the bag model
• D-term and structure of point-like and composed spin-0 particles
• Gravitational form factors within light-cone sum rules at leading order
• On the D-term of the nucleon generalized parton distributions
• Rigorous constraints on the matrix elements of the energy-momentum tensor
• On the role of isospin violation in the pion-nucleon $\sigma$-term
• Forces inside a strongly-coupled scalar nucleon
• Transverse charge distributions of the nucleon and their Abel images
• Global parametrizations of $\pi \pi$ scattering with dispersive constraints: Beyond the S0 wave

Cited by in corpus (9)

• Gravitational form factors of pions, kaons and nucleons from dispersion relations
• Energy-momentum tensor form factor D(t) of proton and neutron
• Reconstruction of Gravitational Form Factors using Generative Machine Learning
• Energy-momentum tensor form factors and spin density distribution in the nucleon calculated in a quantized Skyrme model with vector mesons
• Entanglement, Trace Anomaly and Confinement in QCD
• Nucleon mass: trace anomaly and $\sigma$-terms
• Low-energy scattering of the $J/\psi \pi$ and $J/\psi K$ system
• Origin of the nucleon gravitational form factor $B_N(t)$: Exposition in light-front holographic QCD
• Renormalization of chiral perturbation theory with spinless matter field in curved spacetime