Isospin breaking in the pion-nucleon coupling from QCD sum rules
- Department of Physics, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
- Department of Physics, University of Washington, Box 351560, Seattle, Washington 98195 (United States)
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{sub NN{pi}} coming from isospin violation in the strong interaction. The effect can be attributed primarily to the difference of the quark condensates {l_angle}{bar u}u{r_angle} and {l_angle}{bar d}d{r_angle}. For the splitting (g{sub pp{pi}{sub 0}}{minus}g{sub nn{pi}{sub 0}})/g{sub NN{pi}} we obtain an interval of 1.2{times}10{sup {minus}2} to 3.7{times}10{sup {minus}2}, the uncertainties coming mainly from the input parameters. The charged pion nucleon coupling is found to be the average of g{sub pp{pi}{sub 0}} and g{sub nn{pi}{sub 0}}. Electromagnetic effects are not included. {copyright} {ital 1997} {ital The American Physical Society}
- DOE Contract Number:
- FG06-88ER40427
- OSTI ID:
- 656100
- Journal Information:
- Physical Review, C, Journal Name: Physical Review, C Journal Issue: 6 Vol. 55; ISSN PRVCAN; ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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