New QCD sum rules for nucleon axial-vector coupling constants

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.55.4066· OSTI ID:535731

Lee, F X ^[1]; Leinweber, D B ^[2]; Jin, X ^[3]

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1. TRIUMF, 4004 Wesbrook Mall Vancouver, British Columbia, V6T 2A3 (CANADA)
2. Department of Physics, University of Washington, Seattle, Washington 98195 (United States)
3. TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (CANADA)

Two new sets of QCD sum rules for the nucleon axial-vector coupling constants are derived using the external-field technique and generalized interpolating fields. An in-depth study of the predicative ability of these sum rules is carried out using a Monte Carlo{endash}based uncertainty analysis. The results show that the standard implementation of the QCD sum rule method has only marginal predicative power for the nucleon axial-vector coupling constants, as the relative errors are large. The errors range from approximately 50{percent} to 100{percent} compared to the nucleon mass obtained from the same method, which has only a 10{percent}{endash}25{percent} error. The origin of the large errors is examined. Previous analyses of these coupling constants are based on sum rules that have poor operator product expansion convergence and large continuum contributions. Preferred sum rules are identified and their predictions are obtained. We also investigate the new sum rules with an alternative treatment of the problematic transitions which are not exponentially suppressed in the standard treatment. The alternative treatment provides exponential suppression of their contributions relative to the ground state. Implications for other nucleon current matrix elements are also discussed. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: FC02-94ER40818; FG03-93ER40774; FG06-88ER40427
• OSTI ID: 535731
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 7 Vol. 55; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AXIAL-VECTOR CURRENTS
COUPLING CONSTANTS
CURRENT ALGEBRA
MATRIX ELEMENTS
MONTE CARLO METHOD
NUCLEONS
QUANTUM CHROMODYNAMICS
SUM RULES