Determination of the axial coupling constant $g_A$ in the linear representations of chiral symmetry

Abstract

If a baryon field belongs to a certain linear representation of chiral symmetry of $SU(2)\otimes SU(2)$, the axial coupling constant $g_A$ can be determined algebraically from the commutation relations derived from the superconvergence property of pion-nucleon scattering amplitudes. This establishes an algebraic explanation for the values of $g_A$ of such as the non-relativistic quark model, large-$N_c$ limit and the mirror assignment for two chiral partner nucleons. For the mirror assignment, the axial charges of the positive and negative parity nucleons have opposite signs. Experiments of eta and pion productions are proposed in which the sign difference of the axial charges can be observed.

Comments: 7 pages, proceedings for EMI int. conf. at RCNP, Dec. 2001