Isospin Breaking in the Pion-Nucleon Coupling from QCD Sum Rules

Abstract

We use QCD sum rules for the three point function of a pseudoscalar and two nucleonic currents in order to estimate the charge dependence of the pion nucleon coupling constant $g_{NN\pi }$ coming from isospin violation in the strong interaction. The effect can be attributed primarily to the difference of the quark condensates $<\bar{u}u>$ and $<\bar{d}d>$. For the splitting $(g_{pp{\pi }_0}-g_{nn{\pi }_0})/g_{NN\pi }$ we obtain an interval of $1.2\ast 10^{-2}$ to $3.7\ast 10^{-2}$, the uncertainties coming mainly from the input parameters. The charged pion nucleon coupling is found to be the average of $g_{pp{\pi }_0}$ and $g_{nn{\pi }_0}$. Electromagnetic effects are not included.

18 pages (REVTeX) + 2 figures (as PostScript), to be published in PRC, replaced with final version: inclusion of pi-eta mixing and N -> N* transitions

References in corpus (7)

• Phenomenological Aspects of Isospin Violation in the Nuclear Force
• The Pion-Nucleon Coupling Constant in QCD Sum Rules
• Determination of the pion-nucleon coupling constant from QCD sum rules
• Charge-Symmetry-Breaking Potentials from Isospin-Violating Meson-Baryon Coupling Constants
• The Pion-Nucleon Form Factor From QCD Sum Rules
• Isospin-Violating Meson-Nucleon Vertices as an Alternate Mechanism of Charge-Symmetry Breaking
• Isospin Violations in the Pion-Nucleon System

Cited by in corpus (7)

• The $F/D$ ratio and meson-baryon couplings from QCD sum rules-II
• Meson-baryon couplings and the $F/D$ ratio from QCD sum rules
• On the strong coupling $N^{(\ast )}{N}^{(\ast )}\pi$
• Higher Resonance Contamination of pi NN Couplings Obtained Via the Three-Point Function Method in QCD Sum Rules
• The Coupling of eta Mesons to Quarks and Baryons from D_s^* -> D_s pi^0 Decay
• QCD Sum Rules: Isospin Symmetry Breakings in Pion-Nucleon Couplings
• Analysis of the low-energy ${\pi }^{-}p$ charge-exchange data