Nucleon gravitational form factors
Zhao-Qian Yao, Yin-Zhen Xu, Daniele Binosi, Zhu-Fang Cui, Minghui Ding, Khépani Raya, Craig D. Roberts, J. Rodrı́guez-Quintero, Sebastian M. Schmidt
Abstract
Abstract A symmetry-preserving analysis of strong interaction quantum field equations is used to complete a unified treatment of pion, kaon, and nucleon electromagnetic and gravitational form factors. Findings include a demonstration that the pion near-core pressure is roughly twice that in the proton, so both are significantly greater than that of a neutron star; parton species separations of the nucleon’s three gravitational form factors, in which, inter alia , the glue-to-quark ratio for each form factor is seen to take the same constant value, independent of momentum transfer; and a determination of proton radii orderings, with the mechanical (normal force) radius being less than the mass-energy radius, which is less than the proton charge radius. This body of predictions should prove useful in an era of experiments that will enable them to be tested.