Gravitational Form Factors of the Proton from Lattice QCD

The gravitational form factors (GFFs) of a hadron encode fundamental aspects of its structure, including its shape and size as defined from, e.g., its energy density. This Letter presents a determination of the flavor decomposition of the GFFs of the proton from lattice QCD, in the kinematic region <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mn>0</a:mn><a:mo>≤</a:mo><a:mo>−</a:mo><a:mi>t</a:mi><a:mo>≤</a:mo><a:mn>2</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:msup><a:mi>GeV</a:mi><a:mn>2</a:mn></a:msup></a:math>. The decomposition into up-, down-, strange-quark, and gluon contributions provides first-principles constraints on the role of each constituent in generating key proton structure observables, such as its mechanical radius, mass radius, and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>D</c:mi></c:math> term.