Charge-symmetry-breaking corrections to pseudoscalar meson-nucleon coupling constants due to up-down current quark mass difference and their effects onNNscattering lengths

Abstract

The charge-symmetry-breaking corrections due to the isospin breaking part of the quantum chromodynamic Hamiltonian, determined by the up-down current quark mass difference, $H_{\mathrm{QCD}=\mathrm{half}\left(m_u\mathrm{-}{m}_d\right)(\mathrm{ū}\mathrm{u}\mathrm{-}\mathrm{d}\mathrm{¯}\mathrm{d}}$), on πNN and ηNN coupling constants and their effect on (δa${)}_{\mathrm{CSB}=a_{\mathrm{pp}}\mathrm{-}{a}_{\mathrm{nn}}}$ are estimated. The effects of $H_{\mathrm{QCD}}$ on the pseudoscalar meson-nucleon coupling constants are calculated via ${\pi }^0$-η,η’ mixing, giving rise to charge-symmetry-breaking one-boson-exchange [one-pion-exchange and one-η-exchange] and two-boson-exchange [two-pion-exchange, πη-exchange etc.] potentials. The importance of charge-symmetry-breaking two-boson exchange is emphasized.