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Isospin Breaking in the Nucleon Isovector Axial Charge from QCD Sum Rules by Jin, Xuemin is a scholarly article available to read on EtoBox.

What is Isospin Breaking in the Nucleon Isovector Axial Charge from QCD Sum Rules about?

The isospin breaking in the nucleon isovector axial charge, $g_A^3$, are calculated within the external field QCD sum-rule approach. The isospin violations arising from the difference in up and down current quark masses and in up and down quark condensates are included; electromagnetic effects are not considered. We find $\delta g^3_A/g^3_A \approx (0.5-1.0)\times 10^{-2}$, where $\delta g^3_A = (g^3_A)_p + (g^3_A)_n$ and $ g^3_A = [(g^3_A)_p - (g^3_A)_n]/2$. Using the Goldberger-Treiman relation, we also obtain an estimate of the isospin breaking in the pion-nucleon coupling constant, $(g_{pp\pi_0}-g_{nn\pi_0})/g_{NN\pi} \approx (2-7) \times 10^{-3}$.

Author

Jin, Xuemin

Published

1996

Language

EN