Bibliographic Information: Bhattacharya, S., Cichy, K., Constantinou, M., Gao, X., Metz, A., Miller, J., Mukherjee, S., Petreczky, P., Steffens, F., & Zhao, Y. (2024). Moments of Axial-Vector GPD from Lattice QCD: Quark Helicity, Orbital Angular Momentum, and Spin-Orbit Correlation. arXiv:2410.03539v1 [hep-lat].
Research Objective: This study aims to calculate the Mellin moments of the twist-2 axial-vector generalized parton distribution (GPD) eH(x, ξ, t) at zero skewness (ξ) using lattice QCD, and to analyze these moments to gain insights into the spin structure of the nucleon.
Methodology: The research employs a lattice QCD calculation based on an Nf = 2 + 1 + 1 twisted mass fermions ensemble with clover improvement. The analysis utilizes the short-distance factorization framework on ratio-scheme renormalized quasi-GPD matrix elements. Both iso-vector and iso-scalar cases are considered, utilizing next-to-leading-order perturbative matching.
Key Findings: The study successfully determines the Mellin moments of eH up to the fifth order for the first time. The results indicate a clear signal and expected t-dependence for these moments. The analysis of these moments provides insights into the quark helicity and orbital angular momentum contributions to the nucleon spin, as well as the spin-orbit correlations of the quarks.
Main Conclusions: The calculated moments of the axial-vector GPD offer valuable information about the nucleon spin structure. The study demonstrates the feasibility of extracting higher moments using the employed lattice QCD approach, paving the way for further investigations into the three-dimensional structure of hadrons.
Significance: This research significantly contributes to the understanding of nucleon spin dynamics by providing valuable data on axial-vector GPD moments. The findings have implications for interpreting experimental results from facilities like the Electron-Ion Collider and enhancing theoretical models of nucleon structure.
Limitations and Future Research: The study acknowledges limitations such as neglecting disconnected contributions and gluon mixing in the iso-scalar case. Future research could address these limitations and explore the impact of these contributions on the extracted moments. Additionally, extending the analysis to non-zero skewness would provide a more complete picture of the GPD and nucleon spin structure.
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by Shohini Bhat... at arxiv.org 10-07-2024
https://arxiv.org/pdf/2410.03539.pdfDeeper Inquiries