The dynamic origins of fermionic D-terms

Understand

The D-term is a particle property defined, similarly to the mass and spin, through matrix elements of the energy-momentum tensor.

• It is currently not known experimentally for any particle, but the D-term of the nucleon can be inferred from studies of hard-exclusive reactions.
• In this work we show that the D-term of a spin-1/2 fermion is of dynamical origin: it vanishes for a free fermion.
• This is in pronounced contrast to the bosonic case where already a free spin-0 boson has a non-zero intrinsic D-term as shown in an accompanying work.