May 22 – 26, 2023
IJCLab, Orsay (FRANCE)
Europe/Paris timezone

Nucleon spin decomposition with one dynamical gluon

Not scheduled
Auditorium Joliot Curie (IJCLab, Orsay (FRANCE))

Auditorium Joliot Curie

IJCLab, Orsay (FRANCE)

15, Rue G. Clemenceau 91405 Orsay Cedex FRANCE


Chandan Mondal


There is a well-known puzzle: one of the fundamental properties of the proton, its spin, is not the same as the sum of its constituent quark spins. The gluon's contribution to the proton spin is nonvanishing and likely sizable. Yet, there remain large uncertainties about the gluon’s contribution and resolving this issue is one of the major goals of the upcoming Electron-Ion-Colliders. We address this fundamental issue with a fully relativistic and nonperturbative approach based on a light-front quantized Hamiltonian with QCD input. From this, we calculate the effects from incorporating a dynamical gluon on the proton’s gluon densities, helicity distribution and orbital angular momentum that constitute the proton spin sum rule. We predict about 26% of the proton's spin is carried by the gluon's helicity and about 1.3% by its orbital angular momentum in low-momentum transfer experiments. Our approach also provides a good quality description of the proton's quark distribution functions following QCD scale evolution.

Primary authors

Chandan Mondal siqi Xu Xingbo Zhao Yang Li (University of Science and Technology of China) James Vary

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