Gravitational form factor D of charmonium from shear stress

Based on our recent analysis of the hadronic matrix element of the stress-energy tensor in covariant light front dynamics, we extract the charmonium gravitational form factor D(Q²) from shear stress T¹². This is in contrast to our recent work using the (light-front) energy density T⁺⁻. Indeed, by comparing these two currents, we identify terms that are responsible for the violation of the current conservation. Numerical results based on basis light-front quantization show that the violation effects are small and the D-term extracted from the two currents are close to each other, hence validating our previous work using T⁺⁻.