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Author Aguilar, A.C.; Ferreira, M.N.; Oliveira, B.M.; Papavassiliou, J.; Santos, L.R.
Title Schwinger poles of the three-gluon vertex: symmetry and dynamics Type Journal Article
Year 2023 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 83 Issue 10 Pages 889 - 20pp
Keywords
Abstract The implementation of the Schwinger mechanism endows gluons with a nonperturbative mass through the formation of special massless poles in the fundamental QCD vertices; due to their longitudinal character, these poles do not cause divergences in on-shell amplitudes, but induce detectable effects in the Green's functions of the theory. Particularly important in this theoretical setup is the three-gluon vertex, whose pole content extends beyond the minimal structure required for the generation of a gluon mass. In the present work we analyze these additional pole patterns by means of two distinct, but ultimately equivalent, methods: the Slavnov-Taylor identity satisfied by the three-gluon vertex, and the nonlinear Schwinger-Dyson equation that governs the dynamical evolution of this vertex. Our analysis reveals that the Slavnov-Taylor identity imposes strict model-independent constraints on the associated residues, preventing them from vanishing. Approximate versions of these constraints are subsequently recovered from the Schwinger-Dyson equation, once the elements responsible for the activation of the Schwinger mechanism have been duly incorporated. The excellent coincidence between the two approaches exposes a profound connection between symmetry and dynamics, and serves as a nontrivial self-consistency test of this particular mass generating scenario.
Address [Aguilar, A. C.; Oliveira, B. M.; Santos, L. R.] Univ Campinas UNICAMP, Inst Phys Gleb Wataghin, BR-13083859 Campinas, SP, Brazil, Email: aguilar@ifi.unicamp.br
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:001118963200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5861
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Author Krupczak, R.; da Silva, T.N.; Domingues, T.S.; Luzum, M.; Denicol, G.S.; Gardim, F.G.; Giannini, A.V.; Ferreira, M.N.; Hippert, M.; Noronha, J.; Chinellato, D.D.; Takahashi, J.
Title Causality violations in simulations of large and small heavy-ion collisions Type Journal Article
Year 2024 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 109 Issue 3 Pages 034908 - 12pp
Keywords
Abstract Heavy-ion collisions, such as Pb-Pb or p-Pb, produce extreme conditions in temperature and density that make the hadronic matter transition to a new state, called quark-gluon plasma (QGP). Simulations of heavy-ion collisions provide a way to improve our understanding of the QGP's properties. These simulations are composed of a hybrid description that results in final observables in agreement with accelerators like LHC and RHIC. However, recent works pointed out that these hydrodynamic simulations can display acausal behavior during the evolution in certain regions, indicating a deviation from a faithful representation of the underlying QCD dynamics. To pursue a better understanding of this problem and its consequences, this work simulated two different collision systems, Pb-Pb and p-Pb at root sNN = 5.02 TeV. In this context, our results show that causality violation, even though always present, typically occurs on a small part of the system, quantified by the total energy fraction residing in the acausal region. In addition, the acausal behavior can be reduced with changes in the prehydrodynamic factors and the definition of the bulk-viscous relaxation time. Since these aspects are fairly arbitrary in current simulation models, without solid guidance from the underlying theory, it is reasonable to use the disturbing presence of acausal behavior in current simulations to guide improvements towards more realistic modeling. While this work does not solve the acausality problem, it sheds more light on this issue and also proposes a way to solve this problem in simulations of heavy-ion collisions.
Address [Krupczak, Renata; da Silva, Tiago Nunes] Univ Fed Santa Catarina, Ctr Ciencias Fis & Matemat, Dept Fis, Campus Univ Reitor Joao David Ferreira Lima, BR-88040900 Florianopolis, Brazil, Email: rkrupczak@physik.uni-bielefeld.de;
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:001198699800003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6113
Permanent link to this record