Records |
Author |
Aguilar, A.C.; Ferreira, M.N.; Ibañez, D.; Papavassiliou, J. |
Title |
Schwinger displacement of the quark-gluon vertex |
Type |
Journal Article |
Year |
2023 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
Volume |
83 |
Issue |
10 |
Pages |
967 - 22pp |
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Abstract |
The action of the Schwinger mechanism in pure Yang-Mills theories endows gluons with an effective mass, and, at the same time, induces a measurable displacement to the Ward identity satisfied by the three-gluon vertex. In the present work we turn to Quantum Chromodynamics with two light quark flavors, and explore the appearance of this characteristic displacement at the level of the quark-gluon vertex. When the Schwinger mechanism is activated, this vertex acquires massless poles, whose momentum-dependent residues are determined by a set of coupled integral equations. The main effect of these residues is to displace the Ward identity obeyed by the pole-free part of the vertex, causing modifications to its form factors, and especially the one associated with the tree-level tensor. The comparison between the available lattice data for this form factor and the Ward identity prediction reveals a marked deviation, which is completely compatible with the theoretical expectation for the attendant residue. This analysis corroborates further the self-consistency of this mass-generating scenario in the general context of real-world strong interactions. |
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no |
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yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6080 |
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Author |
Aguilar, A.C.; Ferreira, M.N.; Papavassiliou, J.; Santos, L.R. |
Title |
Four-gluon vertex in collinear kinematics |
Type |
Journal Article |
Year |
2024 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
Volume |
84 |
Issue |
7 |
Pages |
676 - 27pp |
Keywords |
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Abstract |
To date, the four-gluon vertex is the least explored component of the QCD Lagrangian, mainly due to the vast proliferation of Lorentz and color structures required for its description. In this work we present a nonperturbative study of this vertex, based on the one-loop dressed Schwinger-Dyson equation obtained from the 4PI effective action. A vast simplification is brought about by resorting to “collinear” kinematics, where all momenta are parallel to each other, and by appealing to the charge conjugation symmetry in order to eliminate certain color structures. Out of the fifteen form factors that comprise the transversely-projected version of this vertex, two are singled out and studied in detail; the one associated with the classical tensorial structure is moderately suppressed in the infrared regime, while the other diverges logarithmically at the origin. Quite interestingly, both form factors display the property known as “planar degeneracy” at a rather high level of accuracy. With these results we construct an effective charge that quantifies the strength of the four-gluon interaction, and compare it with other vertex-derived charges from the gauge sector of QCD. |
Address |
[Aguilar, A. C.; Santos, L. R.] Univ Campinas UNICAMP, Inst Phys Gleb Wataghin, BR-13083859 Campinas, SP, Brazil, Email: aguilar@ifi.unicamp.br |
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Springer |
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English |
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ISSN |
1434-6044 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001264786100001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6199 |
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Author |
Souza, E.V.; Ferreira, M.N.; Aguilar, A.C.; Papavassiliou, J.; Roberts, C.D.; Xu, S.S. |
Title |
Pseudoscalar glueball mass: a window on three-gluon interactions |
Type |
Journal Article |
Year |
2020 |
Publication ![sorted by Publication field, descending order (down)](img/sort_desc.gif) |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
Volume |
56 |
Issue |
1 |
Pages |
25 - 7pp |
Keywords |
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Abstract |
In pure-glue QCD, gluon-gluon scattering in the J(PC) = 0(-+) channel is described by a very simple equation, especially if one considers just the leading contribution to the scattering kernel. Of all components in this kernel, only the three-gluon vertex, V-mu nu rho, is poorly constrained by contemporary analyses; hence, calculations of 0(-+) glueball properties serve as a clear window onto the character and form of V-mu nu rho. This is important given that many modern calculations of V-mu nu rho predict the appearance of an infrared suppression in the scalar function which comes to modulate the bare vertex after the nonperturbative resummation of interactions. Such behaviour is a peculiar prediction; but we find that the suppression is essential if one is to achieve agreement with lattice-QCD predictions for the 0(-+) glueball mass. Hence, it is likely that this novel feature of V-mu nu rho is real and has observable implications for the spectrum, decays and interactions of all QCD bound-states. |
Address |
[Souza, E. V.] Fed Inst Educ Sci & Technol Piaui, BR-64605500 Picos, Piaui, Brazil, Email: emanuel.veras@ifpi.edu.br; |
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Springer |
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English |
Summary Language |
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Series Volume |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000513948400001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4291 |
Permanent link to this record |