Suppression of Πnn Coupling and Chiral Symmetry
نویسندگان
چکیده
Meson-baryon couplings between positive and negative parity nucleons are investigated using two point correlation functions in the soft meson and the chiral limit. We find that the πNN coupling vanishes due to chiral symmetry, while the ηNN coupling remains finite. We perform an analysis based on the algebraic method for SU(2) chiral symmetry, and find that nucleon axial charges play an essential role for vanishing coupling constants. For an illustration, we construct sigma models with N and N∗, where we discuss their properties from the view point of the chiral symmetry. We also discuss N and N∗ in the viewpoint of chiral partner.
منابع مشابه
ar X iv : h ep - p h / 97 07 30 7 v 1 1 0 Ju l 1 99 7 Suppression of πNN ∗ Coupling and Chiral Symmetry
Meson-baryon couplings between positive and negative parity baryons are investigated using two point correlation functions in the soft meson limit. We find that the πN N * coupling vanishes due to chiral symmetry, while the ηN N * coupling remains finite. We perform an analysis based on the algebraic method for SU (2) and SU (3) chiral symmetry, and find that baryon axial charges play an essent...
متن کاملSuppression of πNN(1535) Coupling in the QCD Sum Rule
The πNN∗ and ηNN∗ coupling constants are studied in the QCD sum rule (N∗ ≡ N(1535)). We investigate the two point functions between the vacuum and a one meson state in the soft meson limit. The operator product expansion is explicitly performed up to terms of dimension eight. We find that gπNN∗ vanishes to this order, while gηNN∗ has a finite contribution. The vanishing of gπNN∗ is a rigorous c...
متن کاملQCD Sum Rules and Chiral Symmetry Breaking
We investigate, in the context of QCD sum rules, the role of Goldstone bosons arising from chiral symmetry breaking, especially on the need of matching the world of hadrons to that of some effective chiral quark theory. We describe how such matching yields predictions on induced condensates which reproduce the observed value of the strong πN N coupling constant. Our result indicate that the obs...
متن کاملcoupling constant
We calculate the π∆∆ coupling gπ0∆++∆++ using light cone QCD sum rule. Our result is gπ0∆++∆++ = (11.8 ± 2.0). We compare various model predictions. PACS numbers: 12.39.Fe, 14.20.Gk The π∆∆ coupling constant g1, like the nucleon axial charge gA, is a basic parameter which enters the loop calculation in all processes involved with delta resonance [1] in chiral perturbation theory. Unfortunately ...
متن کاملParity Violation in − → γ p Compton Scattering
Polarized beam −→γ p Compton scattering provides a theoretically clean way to extract the isovector parity violating pion-nucleon coupling constant h (1) πNN . This channel is more tractable experimentally than the recently proposed extraction of h (1) πNN from the Bedaque-Savage process — polarized target γ −→p compton scattering. The leading parity violating effect is calculated using Heavy B...
متن کامل