Year: 2022
Type: article
Abstract: Using a Poincaré-covariant quark+diquark Faddeev equation and related symmetry-preserving weak interaction current, we deliver parameter-free predictions for the nucleon axialvector form factor, $$G_A(Q^2)$$ G A ( Q 2 ) , on the domain $$0\le x=Q^2/m_N^2\le 10$$ 0 ≤ x = Q 2 / m N 2 ≤ 10 , where $$m_N$$ m N is the nucleon mass. We also provide a detailed analysis of the flavour separation of the proton $$G_A$$ G A into contributions from valence u and d quarks; and with form factors available on such a large $$Q^2$$ Q 2 domain, predictions for the flavour-separated axial-charge light-front transverse spatial density profiles. Our calculated axial charge ratio $$g_A^d/g_A^u=-0.32(2)$$ g A d / g A u = - 0.32 ( 2 ) is consistent with available experimental data and markedly larger in magnitude than the value typical of nonrelativistic quark models. The value of this ratio is sensitive to the strength of axialvector diquark correlations in the Poincaré-covariant nucleon wave function. Working with a realistic axialvector diquark content, the d and u quark transverse density profiles are similar. Some of these predictions could potentially be tested with new data on threshold pion electroproduction from the proton at large $$Q^2$$ Q 2 .
Source: The European Physical Journal A
Authors: Chen Chen, Craig D. Roberts
Language: Latvian
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,390
Awards: G7654887179, G7705497243
OpenAlex ID: W4283695202