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Type: Journal article
Title: Infrared exponent for gluon and ghost propagation in Landau gauge QCD
Author: Lerche, Christoph
von Smekal, Lorenz Johann Maria
Citation: Physical Review D, 2002; 65(12):125006
Publisher: American Physical Society
Issue Date: 2002
ISSN: 1550-7998
School/Discipline: School of Chemistry and Physics
Statement of
Christoph Lerche and Lorenz von Smekal
Abstract: In the covariant description of confinement, one expects the ghost correlations to be infrared enhanced. Assuming ghost dominance, the long-range behavior of gluon and ghost correlations in Landau gauge QCD is determined by one exponent κ. The gluon propagator is infrared finite (vanishing) for κ=1/2 (κ>1/2) which is still under debate. Here, we study the critical exponent and coupling for the infrared conformal behavior from the asymptotic form of the solutions to the Dyson-Schwinger equations in an ultraviolet finite expansion scheme. The value for κ is directly related to the ghost-gluon vertex. Assuming that it is regular in the infrared, one obtains κ≃0.595. This value maximizes the critical coupling αc(κ), yielding αcmax≃(4π/Nc)0.709≈2.97 for Nc=3. For larger κ the vertex acquires an infrared singularity in the gluon momentum; smaller ones imply infrared singular ghost legs. Variations in αc remain within 5% from κ=0.5 to 0.7. Above this range, αc decreases more rapidly with αc→0+ as κ⃗1- which sets the upper bound on κ.
Rights: ©2002 American Physical Society
RMID: 0020063496
DOI: 10.1103/PhysRevD.65.125006
Appears in Collections:Chemistry and Physics publications

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