Form factors of the nucleon axial current
| Autor: | Christian S. Fischer, Jorge Segovia, Craig D. Roberts, Chen Chen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Quark
Nuclear and High Energy Physics Particle physics Nuclear Theory Emergence of hadronic mass High Energy Physics::Lattice Scalar (mathematics) FOS: Physical sciences Nucleus neutrino interactions 01 natural sciences High Energy Physics - Experiment Nuclear Theory (nucl-th) High Energy Physics - Experiment (hep-ex) High Energy Physics - Phenomenology (hep-ph) High Energy Physics - Lattice Pion Schwinger functions 0103 physical sciences Nuclear Experiment (nucl-ex) Nuclear Experiment 010306 general physics Physics 010308 nuclear & particles physics Diquark correlations High Energy Physics - Lattice (hep-lat) Nucleon axial current High Energy Physics::Phenomenology Form factor (quantum field theory) Charge (physics) Faddeev equation lcsh:QC1-999 Diquark Pseudoscalar High Energy Physics - Phenomenology High Energy Physics::Experiment Nucleon lcsh:Physics |
| Zdroj: | Physics Letters Physics Letters B, Vol 815, Iss, Pp 136150-(2021) |
| Popis: | A symmetry-preserving Poincar\'e-covariant quark+diquark Faddeev equation treatment of the nucleon is used to deliver parameter-free predictions for the nucleon's axial and induced pseudoscalar form factors, $G_A$ and $G_P$, respectively. The result for $G_A$ can reliably be represented by a dipole form factor characterised by an axial charge $g_A=G_A(0)=1.25(3)$ and a mass-scale $M_A = 1.23(3) m_N$, where $m_N$ is the nucleon mass; and regarding $G_P$, the induced pseudoscalar charge $g_p^\ast = 8.80(23)$, the ratio $g_p^\ast/g_A = 7.04(22)$, and the pion pole dominance Ansatz is found to provide a reliable estimate of the directly computed result. The ratio of flavour-separated quark axial charges is also calculated: $g_A^d/g_A^u=-0.16(2)$. This value expresses a marked suppression of the size of the $d$-quark component relative to that found in nonrelativistic quark models and owes to the presence of strong diquark correlations in the nucleon Faddeev wave function -- both scalar and axial-vector, with the scalar diquark being dominant. The predicted form for $G_A$ should provide a sound foundation for analyses of the neutrino-nucleus and antineutrino-nucleus cross-sections that are relevant to modern accelerator neutrino experiments. Comment: 8 pages, 6 figures, 2 tables. Accepted for publication in Phys. Lett. B |
| Databáze: | OpenAIRE |
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