Evidence of ghost suppression in gluon mass scale dynamics

Aguilar, A. C.; Binosi, Daniele; Figueiredo, Clara Teixeira; Papavassiliou, Joannis

doi:10.1140/epjc/s10052-018-5679-2

Cited by 54 publications

(72 citation statements)

References 97 publications

(168 reference statements)

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“…(b) The emergence of the component m 2 (q 2 ) is triggered by the non-Abelian realization of the well-known Schwinger mechanism [82,83] for gauge boson mass generation. This latter mechanism is activated through the inclusion of longitudinally coupled massless poles into the three-gluon vertex that enters in the SDE governing the evolution of ∆ −1 (q 2 ) [54, [84][85][86][87].…”

Section: A Basic Concepts and Key Relationsmentioning

confidence: 99%

Gluon propagator and three-gluon vertex with dynamical quarks

et al. 2020

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We present a detailed analysis of the kinetic and mass terms associated with the Landau gauge gluon propagator in the presence of dynamical quarks, and a comprehensive dynamical study of certain special kinematic limits of the three-gluon vertex. Our approach capitalizes on results from recent lattice simulations with (2+1) domain wall fermions, a novel nonlinear treatment of the gluon mass equation, and the nonperturbative reconstruction of the longitudinal three-gluon vertex from its fundamental Slavnov-Taylor identities. Particular emphasis is placed on the persistence of the suppression displayed by certain combinations of the vertex form factors at intermediate and low momenta, already known from numerous pure Yang-Mills studies. One of our central findings is that the inclusion of dynamical quarks moderates the intensity of this phenomenon only mildly, leaving the asymptotic low-momentum behavior unaltered, but displaces the characteristic "zero crossing" deeper into the infrared region. In addition, the effect of the three-gluon vertex is explored at the level of the renormalization-group invariant combination corresponding to the effective gauge coupling, whose size is considerably reduced with respect to its counterpart obtained from the ghost-gluon vertex. The main upshot of the above considerations is the further confirmation of the tightly interwoven dynamics between the two-and three-point sectors of QCD.

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Section: A Basic Concepts and Key Relationsmentioning

confidence: 99%

Gluon propagator and three-gluon vertex with dynamical quarks

et al. 2020

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“…where m g = 500 MeV is a gluon mass scale generated dynamically in QCD [36][37][38][39], and α IR can be interpreted as the interaction strength in the infrared [40][41][42].…”

Section: Contact Interaction: Featuresmentioning

confidence: 99%

Masses of light and heavy mesons and baryons: A unified picture

et al. 2019

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We compute masses of positive parity spin-1/2 and 3/2 baryons composed of u, d, s, c and b quarks in a quark-diaquark picture. The mathematical foundation for this analysis is implemented through a symmetry-preserving Schwinger-Dyson equations treatment of a vector-vector contact interaction, which preserves key features of quantum chromodynamics, such as confinement, chiral symmetry breaking and low energy Goldberger-Treiman relations. This study requires a computation of diquark correlations containing these quarks which in turn are readily inferred from solving the Bethe-Salpeter equations of the corresponding mesons. Therefore, it serves as a unified formalism for a multitude of mesons and baryons. It builds on our previous works on the study of masses, decay constants and form factors of quarkonia and light mesons, employing the same model. We use two sets of parameters, one which remains exactly the same for both the light and heavy sector hadrons, and another where the coupling strength is allowed to evolve according to the available mass scales of quarks. Our results are in very good agreement with the existing experimental data as well as predictions of other theoretical approaches whenever comparison is possible.

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“…As has been shown in [3], this crucial feature persists at the non-perturbative level, as a consequence of the simple WIs satisfied by the full vertices appearing in the diagrams of Fig. (1), defining the BFM SD equation for ∆ µν (q) [4].…”

Section: Pacsmentioning

confidence: 53%

“…The connection between PT and BFM, known to persist to all orders (last two articles in [2]), affirms that the (gauge-independent) PT effective n-point functions coincide with the (gaugedependent) BFM n-point functions provided that the latter are computed in the Feynman gauge. In this talk we report recent progress on the issue of gluon mass generation in the PT-BFM scheme [3].…”

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On dynamical gluon mass generation

Aguilar

Papavassiliou

The IVth International Conference on Quarks and Nuclear Physics

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Abstract. The effective gluon propagator constructed with the pinch technique is governed by a SchwingerDyson equation with special structure and gauge properties, that can be deduced from the correspondence with the background field method. Most importantly the non-perturbative gluon self-energy is transverse order-by-order in the dressed loop expansion, and separately for gluonic and ghost contributions, a property which allows for a meanigfull truncation. A linearized version of the truncated Schwinger-Dyson equation is derived, using a vertex that satisfies the required Ward identity and contains massless poles. The resulting integral equation, subject to a properly regularized constraint, is solved numerically, and the main features of the solutions are briefly discussed. It is well-known that one of the main theoretical problems when dealing with Schwinger-Dyson (SD) equations is that they are built out of unphysical off-shell Green's functions; thus, the extraction of reliable physical information depends crucially on delicate all-order cancellations, which may be inadvertently distorted in the process of the truncation. The truncation scheme based on the pinch technique (PT) [1,2] implements a drastic modification at the level of the building blocks of the SD series. The PT enables the construction of new, effective Green's functions endowed with very special properties; most importantly, they are independent of the gauge-fixing parameter, and satisfy QED-like Ward identities (WI) instead of the usual Slavnov-Taylor identities. The upshot of this approach would then be to trade the conventional SD series for another, written in terms of the new Green's functions, and then truncate this new series, by keeping only a few terms in a "dressed-loop" expansion, maintaining exact gauge-invariance. Of central importance in this context is the connection between the PT and the Background Field Method (BFM), a special gauge-fixing procedure that preserves the symmetry of the action under ordinary gauge transformations with respect to the background (classical) gauge field A a µ . As a result, the background n-point functions satisfy QED-like all-order WIs. The connection between PT and BFM, known to persist to all orders (last two articles in [2]), affirms that the (gauge-independent) PT effective n-point functions coincide with the (gaugedependent) BFM n-point functions provided that the latter are computed in the Feynman gauge. In this talk we report recent progress on the issue of gluon mass generation in the PT-BFM scheme [3]. PACSWe first define some basic quantities. There are two gluon propagators appearing in this problem, ∆ µν (q) and ∆ µν (q), denoting the background and quantum gluon propagator, respectively. Defining P µν (q) = g µν − q µ q ν q 2 , we have that ∆ µν (q), in the Feynman gauge is given byThe gluon self-energy, Π µν (q), has the form Π µν (q) = P µν (q) Π(q 2 ), and ∆ −1 (q 2 ) = q 2 + i Π(q 2 ). Exactly analogous definitions relate ∆ µν (q) with Π µν (q).As is widely known, in the conven...

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Evidence of ghost suppression in gluon mass scale dynamics

Cited by 54 publications

References 97 publications

Gluon propagator and three-gluon vertex with dynamical quarks

Gluon propagator and three-gluon vertex with dynamical quarks

Masses of light and heavy mesons and baryons: A unified picture

On dynamical gluon mass generation

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