New Ghost States in SU(3) Gauge Field Theory

Nuclear Physics B, 1992

Starting from the Liouville null-vectors in theories of c <1 matter coupled to 2D gravity, we describe a procedure to explicitly construct elements of the BRS cohomology of ghost number ±1. A crucial step in the analysis concerns the existence of null-states in the Liouville Fock module, for which a general criterion is obtained. The physical states are shown to satisfy a set of "descent equations", and we compute their two-point function on the sphere. Our results are illustrated by a number of examples. 0550-3213/92/$05.00 © 1992 -Elsevier Science Publishers B.V. All rights reserved * This differs from the conventions used in various places in the literature, including ref. [81,where the true vacuum has ghost number + 1.

Physical Review D, 2003

To investigate the possibility of a ghost-antighost condensate the coupled Dyson-Schwinger equations for the gluon and ghost propagators in Yang-Mills theories are derived in general covariant gauges, including ghost-antighost symmetric gauges. The infrared behaviour of these two-point functions is studied in a bare-vertex truncation scheme which has proven to be successful in Landau gauge. In all linear covariant gauges the same infrared behaviour as in Landau gauge is found: The gluon propagator is infrared suppressed whereas the ghost propagator is infrared enhanced. This infrared singular behaviour provides indication against a ghost-antighost condensate. In the ghost-antighost symmetric gauges we find that the infrared behaviour of the gluon and ghost propagators cannot be determined when replacing all dressed vertices by bare ones. The question of a BRST invariant dimension two condensate remains to be further studied.

Physical Review D, 2008

We present rigorous upper and lower bounds for the momentum-space ghost propagator G(p) of Yang-Mills theories in terms of the smallest nonzero eigenvalue (and of the corresponding eigenvector) of the Faddeev-Popov matrix. We apply our analysis to data from simulations of SU(2) lattice gauge theory in Landau gauge, using the largest lattice sizes to date. Our results suggest that, in three and in four space-time dimensions, the Landau-gauge ghost propagator is not enhanced as compared to its tree-level behavior. This is also seen in plots and fits of the ghost dressing function. In the two dimensional case, on the other hand, we find that G(p) diverges as p^{-2-2 kappa} with kappa \approx 0.15, in agreement with Ref. [1]. We note that our discussion is general, although we make an application only to pure gauge theory in Landau gauge. Most of our simulations have been performed on the IBM supercomputer at the University of Sao Paulo.

Physical Review D, 2006

Infrared features of the ghost propagator of color diagonal and color antisymmetric ghost propagator of quenched SU(2) and quenched SU(3) are compared with those of unquenched Kogut-Susskind fermion SU(3) lattice Landau gauge.

2002

We study the ghost sector of vacuum string field theory where the BRST operator Q is given by the midpoint insertion proposed by Gaiotto, Rastelli, Sen and Zwiebach. We introduce a convenient basis of half-string modes in terms of which Q takes a particularly simple form. We show that there exists a field redefinition which reduces the ghost sector field equation to a pure projection equation for string fields satisfying the constraint that the ghost number is equally divided over the left-and right halves of the string. When this constraint is imposed, vacuum string field theory can be reformulated as a U (∞) cubic matrix model. Ghost sector solutions can be constructed from projection operators on half-string Hilbert space just as in the matter sector. We construct the ghost sector equivalent of various well-known matter sector projectors such as the sliver, butterfly and nothing states.

Physical Review D, 2009

We study the momentum dependence of the ghost propagator and of the space and time components of the gluon propagator at equal time in pure SU (3) lattice Coulomb gauge theory carrying out a joint analysis of data collected independently at RCNP Osaka and Humboldt University Berlin. We focus on the scaling behavior of these propagators at β = 5.8, . . . , 6.2 and apply a matching technique to relate the data for the different lattice cutoffs. Thereby, lattice artifacts are found to be rather strong for both instantaneous gluon propagators at large momentum. As a byproduct we obtain the respective lattice scale dependences a(β) for the transversal gluon and the ghost propagator which indeed run faster with β than two-loop running, but slightly slower than what is known from the Necco-Sommer analysis of the heavy quark potential. The abnormal a(β) dependence as determined from the instantaneous time-time gluon propagator, D44, remains a problem, though. The role of residual gauge-fixing influencing D44 is discussed.

Nuclear Physics B, 1998

Fermionic and bosonic ghost systems are defined each in terms of a single vertex algebra which admits a one-parameter family of conformal structures. The observation that these structures are related to each other provides a simple way to obtain character formulae for a general twisted module of a ghost system. The U (1) symmetry and its subgroups that underly the twisted modules also define an infinite set of invariant vertex subalgebras. Their structure is studied in detail from a W-algebra point of view with particular emphasis on Z N-invariant subalgebras of the fermionic ghost system.

Nuclear Physics B, 1988

Geometrical aspects of the BRST quantization of charged antisymmetric tensor fields and string fields are studied within the framework of the Batalin and Vilkovisky method. In both cases, candidate anomalies which obey the Wess-Zumino consistency conditions are given.

Nuclear Physics B - Proceedings Supplements, 2005

The dependence of the Landau gauge gluon and ghost propagators on the choice of Gribov copies is studied in pure SU (3) lattice gauge theory. Whereas the influence on the gluon propagator is small, the ghost propagator becomes clearly affected by the copies in the infrared region. We compare our data with the infrared exponents predicted by the Dyson-Schwinger equation approach.

Few-Body Systems, 2009

The results of Coulomb gauge and Landau gauge lattice QCD simulation do not agree completely with continuum theory. There are indications that the ghost propagator in the infrared region has strong fluctuation whose modulus is compatible with that of the color diagonal ghost propagator. After presenting lattice simulation of configurations produced with Kogut-Susskind fermion (MILC collaboration) and those with domain wall fermion (RBC/UKQCD collaboration), I investigate in triple gluon vertex and the ghost-gluon-ghost vertex how the square of the color antisymmetric ghost contributes. Then the effect of the vertex correction to the gluon propagator and the ghost propagator is investigated.