Axial coupling constant in a magnetic background

Abstract

The nucleon axial coupling constant $g_A$ is calculated in the presence of an external uniform magnetic field using finite energy sum rules. The correlation function of proton, neutron and axial-vector currents is calculated both the hadronic and the QCD sector. Once the axial contribution in the form factor is isolated, a double sum rule is considered, i.e., the usual QCD contour integration for the external moments of both the proton and neutron current. The effects of the external magnetic field come mainly through the in-medium current-nucleon coupling constants ${\lambda }_N(B)$ and the hadronic thresholds $s_0(B)$ provided by the nucleon-nucleon correlators. As a result, the axial coupling constant decreases in the presence of the magnetic field.

6 pages, 5 figures. The case of average flavor approximation was removed. Accepted for publication in PRD

References in corpus (1)

• QCD sum rules for magnetically induced mixing between ${\eta }_c$ and $J/\psi$

Cited by in corpus (6)

• Nucleon axial-vector coupling constant in magnetar environments
• Magnetic field dependence of the neutral pion longitudinal screening mass in the linear sigma model with quarks
• Strongly interacting matter in extreme magnetic fields
• Quark anomalous magnetic moment in an extreme magnetic background from perturbative QCD
• The Yukawa potential under weak magnetic field
• Finite-energy sum rules at finite chemical potential and zero temperature