The Weak parity violating pion - nucleon coupling
Journal
Phys. Lett.
Journal Volume
B367
Pages
21-27
Date Issued
1995-11
Author(s)
Abstract
We use QCD sum rules to obtain the weak parity-violating pion-nucleon coupling constant fπNN. We find that fπNN ≈ 2 × 10-8, about an order of magnitude smaller than the "best estimates" based on quark models. This result follows from the cancellation between perturbative and nonperturbative QCD processes not found in quark models, but explicit in the QCD sum rule method. Our result is consistent with the experimental upper limit found from 18F parity-violating measurements.
Type
journal article