Light-front transverse profiles of scalar and spin-two chromoelectric EMT responses in near-threshold charmonium probes

Abstract

I construct light-front transverse profile functions for the scalar and spin-two chromoelectric energy-momentum-tensor responses selected by compact-charmonium probes of the proton. The scalar branch is the anomaly and sigma amplitude, while the spin-two branch contains the gravitational combination $3B_i(t)-D_i(t)=6J_i(t)-3A_i(t)-D_i(t)$ rather than $A_i(t)$ alone. In the Drell-Yan frame, these two amplitudes define normalized transverse response profiles whose integrated ratio reproduces the forward light-front spin-two/scalar strength, while the finite transverse-distance behavior is sensitive to the relative scalar and gravitational slopes. The construction gives a spatial representation of the chromoelectric EMT projection without interpreting a measured near-threshold slope as a model-independent static three-dimensional mass radius.

Comments: 9 pages, 4 figures