Nucleon relativistic weak-neutral axial-vector four-current distributions

Abstract Relativistic full weak-neutral axial-vector four-current distributions inside a general spin- 1 2 $$ \frac{1}{2} $$ hadron are systematically studied for the first time, where the second-class current contribution associated with the induced pseudotensor form factor (FF) is included. We cle...

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Bibliographic Details
Main Author: Yi Chen
Format: Article
Language:English
Published: SpringerOpen 2025-04-01
Series:Journal of High Energy Physics
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Online Access:https://doi.org/10.1007/JHEP04(2025)132
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Summary:Abstract Relativistic full weak-neutral axial-vector four-current distributions inside a general spin- 1 2 $$ \frac{1}{2} $$ hadron are systematically studied for the first time, where the second-class current contribution associated with the induced pseudotensor form factor (FF) is included. We clearly demonstrate that the 3D axial charge distribution, being parity-odd in the Breit frame, is in fact related to the induced pseudotensor FF G T Z Q 2 $$ {G}_T^Z\left({Q}^2\right) $$ rather than the axial FF G A Z Q 2 $$ {G}_A^Z\left({Q}^2\right) $$ . We study the frame-dependence of full axial-vector four-current distributions for a moving hadron, and compare them with their light-front counterparts. We revisit the role played by the Melosh rotation, and understand more easily and intuitively the origins of distortions appearing in light-front distributions (relative to the Breit frame ones) using the conjecture that we propose in this work. In particular, we show that the second-class current contribution, although explicitly included, does not contribute in fact to the mean-square axial and spin radii. We finally illustrate our results in the case of a proton using the weak-neutral axial-vector FFs extracted from experimental data.
ISSN:1029-8479