Gravitational form factor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math> 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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>D</a:mi><a:mo stretchy="false">(</a:mo><a:msup><a:mi>Q</a:mi><a:mn>2</a:mn></a:msup><a:mo stretchy="false">)</a:mo></a:math> from shear stress <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msup><e:mi>T</e:mi><e:mn>12</e:mn></e:msup></e:math>. This is in contrast to our recent work using the (light-front) energy density <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:msup><g:mi>T</g:mi><g:mrow><g:mo>+</g:mo><g:mo>−</g:mo></g:mrow></g:msup></g:math>. 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 <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>D</i:mi></i:math> term extracted from the two currents are close to each other, hence validating our previous work using <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:msup><k:mi>T</k:mi><k:mrow><k:mo>+</k:mo><k:mo>−</k:mo></k:mrow></k:msup></k:math>.