Toward the Determination of the Gluon Helicity Distribution in the Nucleon from Lattice Quantum Chromodynamics
Physical Review D
We present the first exploratory lattice quantum chromodynamics (QCD) calculation of the polarized gluon Ioffe-time pseudodistribution in the nucleon. The Ioffe-time pseudodistribution provides a frame-independent and gauge-invariant framework to determine the gluon helicity in the nucleon from first principles. We employ a high-statistics computation using a 323 × 64 lattice ensemble characterized by a 358 MeV pion mass and a 0.094 fm lattice spacing. We establish the pseudodistribution approach as a feasible method to address the proton spin puzzle with successive improvements in statistical and systematic uncertainties anticipated in the future. Within the statistical precision of our data, we find a good comparison between the lattice determined polarized gluon Ioffe-time distribution and the corresponding expectations from the state-of-the-art global analyses. We find a hint for a nonzero gluon spin contribution to the proton spin from the model-independent extraction of the gluon helicity pseudodistribution over a range of Ioffe-time, ν ≲ 9.
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Original Publication Citation
Egerer, C., Joó, B., Karpie, J., Karthik, N., Khan, T., Monahan, C., Morris, W., Orginos, K., Radyushkin, A., Richards, D., Romero Alcalde, E., Sufian, R., & Zafeiropoulos, S. (2022). Toward the determination of the gluon helicity distribution in the nucleon from lattice quantum chromodynamics. Physical Review D, 106, 1-22, Article 094511. https://doi.org/10.1103/PhysRevD.106.094511
Egerer, Colin; Joó, Bálint; Karpie, Joseph; Karthik, Nikhil; Khan, Tanjib; Monahan, Christopher J.; Morris, Wayne; Orginos, Kostas; Radyushkin, Anatoly; Richards, David G.; Romero, Eloy; Sabbir Sufian, Raza; and Zafeiropoulos, Savvas, "Toward the Determination of the Gluon Helicity Distribution in the Nucleon from Lattice Quantum Chromodynamics" (2022). Physics Faculty Publications. 708.