Thursday·May 9, 2019

[Submitted on 7 May 2019] (cross-list from hep-ph)

Partonic angular momentum in the nucleon's chiral periphery

Carlos Granados🇺🇸 · Christian Weiss🇺🇸

We study the nucleon's partonic angular momentum (AM) content at peripheral transverse distances $b=\mathcal{O}(M_{\pi }^{-1})$, where the structure is governed by chiral dynamics. We compute the nucleon form factors of the energy-momentum tensor in chiral effective field theory (ChEFT) and construct the transverse densities of AM at fixed light-front time. In the periphery the spin density is suppressed, and the AM is predominantly orbital. In the first-quantized representation of ChEFT in light-front form, the field-theoretical AM density coincides with the quantum-mechanical orbital AM density of the soft pions in the nucleon's periphery.