Gravitational Form Factors in the Axial Sector from an AdS/QCD Model

TL;DR

This paper computes gravitational form factors of pions and axial vector mesons using an AdS/QCD model, revealing their spatial distributions and connecting one form factor to the pion's parton distribution moments.

Contribution

It provides the first calculation of axial sector gravitational form factors in a hard wall AdS/QCD model, linking them to parton distribution sum rules.

Findings

Pion gravitational form factor relates to the second moment of its GPD.

Both pion and axial vector mesons are more compact in gravitational form than electromagnetic.

The model offers insights into the internal structure of mesons via gravitational form factors.

Abstract

We calculate the stress tensor, or energy-momentum tensor, form factors of the pion and of axial vector mesons in the chiral limit of a hard wall AdS/CFT model of QCD. One (of the two) pion gravitational form factors is directly related to the second moment of the pion generalized parton distribution, thus providing a sum rule for the latter. As was also the case for vector mesons, both the pion and the axial vector mesons appear strikingly more compact measured by the gravitational form factor than by the electromagnetic form factor.