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	Author	Aguilar, A.C.; Ferreira, M.N.; Papavassiliou, J.
	Title	Novel sum rules for the three-point sector of QCD			Type	Journal Article
	Year	2020	Publication	European Physical Journal C	Abbreviated Journal	Eur. Phys. J. C
	Volume	80	Issue	9	Pages	887 - 18pp
	Keywords
	Abstract	For special kinematic configurations involving a single momentum scale, certain standard relations, originating from the Slavnov-Taylor identities of the theory, may be interpreted as ordinary differential equations for the “kinetic term” of the gluon propagator. The exact solutions of these equations exhibit poles at the origin, which are incompatible with the physical answer, known to diverge only logarithmically; their elimination hinges on the validity of two integral conditions that we denominate “asymmetric” and “symmetric” sum rules, depending on the kinematics employed in their derivation. The corresponding integrands contain components of the three-gluon vertex and the ghost-gluon kernel, whose dynamics are constrained when the sum rules are imposed. For the numerical treatment we single out the asymmetric sum rule, given that its support stems predominantly from low and intermediate energy regimes of the defining integral, which are physically more interesting. Adopting a combined approach based on Schwinger-Dyson equations and lattice simulations, we demonstrate how the sum rule clearly favors the suppression of an effective form factor entering in the definition of its kernel. The results of the present work offer an additional vantage point into the rich and complex structure of the three-point sector of QCD.
	Address	[Aguilar, A. C.; Ferreira, M. N.] Univ Estadual Campinas, Inst Phys Gleb Wataghin, UNICAMP, BR-13083859 Campinas, SP, Brazil, Email: aguilar@ifi.unicamp.br
	Corporate Author				Thesis
	Publisher	Springer	Place of Publication		Editor
	Language	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:000576141200005			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	4559
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	Author	Aguilar, A.C.; Ferreira, M.N.; Papavassiliou, J.
	Title	Gluon dynamics from an ordinary differential equation			Type	Journal Article
	Year	2021	Publication	European Physical Journal C	Abbreviated Journal	Eur. Phys. J. C
	Volume	81	Issue	1	Pages	54 - 20pp
	Keywords
	Abstract	We present a novel method for computing the nonperturbative kinetic term of the gluon propagator from an ordinary differential equation, whose derivation hinges on the central hypothesis that the regular part of the three-gluon vertex and the aforementioned kinetic term are related by a partial Slavnov-Taylor identity. The main ingredients entering in the solution are projection of the three-gluon vertex and a particular derivative of the ghost-gluon kernel, whose approximate form is derived from a Schwinger-Dyson equation. Crucially, the requirement of a pole-free answer determines the initial condition, whose value is calculated from an integral containing the same ingredients as the solution itself. This feature fixes uniquely, at least in principle, the form of the kinetic term, once the ingredients have been accurately evaluated. In practice, however, due to substantial uncertainties in the computation of the necessary inputs, certain crucial components need be adjusted by hand, in order to obtain self-consistent results. Furthermore, if the gluon propagator has been independently accessed from the lattice, the solution for the kinetic term facilitates the extraction of the momentum-dependent effective gluon mass. The practical implementation of this method is carried out in detail, and the required approximations and theoretical assumptions are duly highlighted.
	Address	[Aguilar, A. C.; Ferreira, M. N.] 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	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:000611993400002			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	4730
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	Author	Cui, Z.F.; Ding, M.; Morgado, J.M.; Raya, K.; Binosi, D.; Chang, L.; Papavassiliou, J.; Roberts, C.D.; Rodriguez-Quintero, J.; Schmidt, S.M.
	Title	Concerning pion parton distributions			Type	Journal Article
	Year	2022	Publication	European Physical Journal A	Abbreviated Journal	Eur. Phys. J. A
	Volume	58	Issue	1	Pages	10 - 14pp
	Keywords
	Abstract	Analyses of the pion valence-quark distribution function (DF), u(pi) (x; sigma), which explicitly incorporate the behaviour of the pion wave function prescribed by quantum chromodynamics (QCD), predict u(pi) (x similar or equal to 1; sigma) similar to (1 – x)(beta(sigma)), beta(sigma greater than or similar to m(p)) > 2, where mp is the proton mass. Nevertheless, more than forty years after the first experiment to collect data suitable for extracting the x similar or equal to 1 behaviour of up, the empirical status remains uncertain because some methods used to fit existing data return a result for up that violates this constraint. Such disagreement entails one of the following conclusions: the analysis concerned is incomplete; not all data being considered are a true expression of qualities intrinsic to the pion; or QCD, as it is currently understood, is not the theory of strong interactions. New, precise data are necessary before a final conclusion is possible. In developing these positions, we exploit a single proposition, viz. there is an effective charge which defines an evolution scheme for parton DFs that is all-orders exact. This proposition has numerous corollaries, which can be used to test the character of any DF, whether fitted or calculated.
	Address	[Cui, Z. -F.; Roberts, C. D.] Nanjing Univ, Sch Phys, Nanjing 210093, Jiangsu, Peoples R China, Email: binosi@ectstar.eu;
	Corporate Author				Thesis
	Publisher	Springer	Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1434-6001	ISBN		Medium
	Area		Expedition		Conference
	Notes	WOS:000746605900001			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5083
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	Author	MoEDAL Collaboration (Acharya, B. et al); Musumeci,E.; Mitsou, V.A.; Papavassiliou, J.; Ruiz de Austri, R.; Santra, A.; Vento, V.; Vives, O.
	Title	Search for highly-ionizing particles in pp collisions at the LHC's Run-1 using the prototype MoEDAL detector			Type	Journal Article
	Year	2022	Publication	European Physical Journal C	Abbreviated Journal	Eur. Phys. J. C
	Volume	82	Issue	8	Pages	694 - 16pp
	Keywords
	Abstract	A search for highly electrically charged objects (HECOs) and magnetic monopoles is presented using 2.2 fb(-1) of p – p collision data taken at a centre of mass energy (E-CM) of 8 TeV by the MoEDAL detector during LHC's Run-1. The data were collected using MoEDAL's prototype Nuclear Track Detectord array and the Trapping Detector array. The results are interpreted in terms of Drell-Yan pair production of stable HECO and monopole pairs with three spin hypotheses (0, 1/2 and 1). The search provides constraints on the direct production of magnetic monopoles carrying one to four Dirac magnetic charges and with mass limits ranging from 590 GeV/c(2) to 1 TeV/c(2). Additionally, mass limits are placed on HECOs with charge in the range 10e to 180e, where e is the charge of an electron, for masses between 30 GeV/c(2) and 1 TeV/c(2).
	Address	[Acharya, B.; Alexandre, J.; Ellis, J. R.; Fairbairn, M.; Mavromatos, N. E.; Sakellariadou, M.; Sarkar, S.] Kings Coll London, Phys Dept, Theoret Particle Phys & Cosmol Grp, London, England, Email: Laura.Patrizii@bo.infn.il;
	Corporate Author				Thesis
	Publisher	Springer	Place of Publication		Editor
	Language	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:000838674800001			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5326
Permanent link to this record



	Author	Aguilar, A.C.; Ferreira, M.N.; Oliveira, B.M.; Papavassiliou, J.
	Title	Schwinger-Dyson truncations in the all-soft limit: a case study			Type	Journal Article
	Year	2022	Publication	European Physical Journal C	Abbreviated Journal	Eur. Phys. J. C
	Volume	82	Issue	11	Pages	1068 - 15pp
	Keywords
	Abstract	We study a special Schwinger-Dyson equation in the context of a pure SU(3) Yang-Mills theory, formulated in the background field method. Specifically, we consider the corresponding equation for the vertex that governs the interaction of two background gluons with a ghost-antighost pair. By virtue of the background gauge invariance, this vertex satisfies a naive Slavnov-Taylor identity, which is not deformed by the ghost sector of the theory. In the all-soft limit, where all momenta vanish, the form of this vertex may be obtained exactly from the corresponding Ward identity. This special result is subsequently reproduced at the level of the Schwinger-Dyson equation, by making extensive use of Taylor's theorem and exploiting a plethora of key relations, particular to the background field method. This information permits the determination of the error associated with two distinct truncation schemes, where the potential advantage from employing lattice data for the ghost dressing function is quantitatively assessed.
	Address	[Aguilar, A. C.; Oliveira, B. M.] 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	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:000889065200003			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5426
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	Author	Aguilar, A.C.; Ferreira, M.N.; Ibañez, D.; Oliveira, B.M.; Papavassiliou, J.
	Title	Patterns of gauge symmetry in the background field method			Type	Journal Article
	Year	2023	Publication	European Physical Journal C	Abbreviated Journal	Eur. Phys. J. C
	Volume	83	Issue	1	Pages	86 - 20pp
	Keywords
	Abstract	The correlation functions of Yang-Mills theories formulated in the background field method satisfy linear Slavnov-Taylor identities, which are naive generalizations of simple tree level relations, with no deformations originating from the ghost-sector of the theory. In recent years, a stronger version of these identities has been found to hold at the level of the background gluon self-energy, whose transversality is enforced separately for each special block of diagrams contributing to the gluon Schwinger-Dyson equation. In the present work we demonstrate by means of explicit calculations that the same distinct realization of the Slavnov-Taylor identity persists in the case of the background three-gluon vertex. The analysis is carried out at the level of the exact Schwinger-Dyson equation for this vertex, with no truncations or simplifying assumptions. The demonstration entails the contraction of individual vertex diagrams by the relevant momentum, which activates Slavnov-Taylor identities of vertices and multi-particle kernels nested inside these graphs; the final result emerges by virtue of a multitude of extensive cancellations, without the need of performing explicit integrations. In addition, we point out that background Ward identities amount to replacing derivatives of propagators by zero-momentum background-gluon insertions, in exact analogy to standard properties of Abelian gauge theories. Finally, certain potential applications of these results are briefly discussed.
	Address	[Aguilar, A. C.; Oliveira, B. M.] 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	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:000923274000003			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5481
Permanent link to this record



	Author	Aguilar, A.C.; Ferreira, M.N.; Papavassiliou, J.; Santos, L.R.
	Title	Planar degeneracy of the three-gluon vertex			Type	Journal Article
	Year	2023	Publication	European Physical Journal C	Abbreviated Journal	Eur. Phys. J. C
	Volume	83	Issue	6	Pages	549 - 20pp
	Keywords
	Abstract	We present a detailed exploration of certain outstanding features of the transversely-projected three-gluon vertex, using the corresponding Schwinger-Dyson equation in conjunction with key results obtained from quenched lattice simulations. The main goal of this study is the scrutiny of the approximate property denominated “planar degeneracy”, unveiled when the Bose symmetry of the vertex is properly exploited. The planar degeneracy leads to a particularly simple parametrization of the vertex, reducing its kinematic dependence to essentially a single variable. Our analysis, carried out in the absence of dynamical quarks, reveals that the planar degeneracy is particularly accurate for the description of the form factor associated with the classical tensor, for a wide array of arbitrary kinematic configurations. Instead, the remaining three form factors display considerable violations of this property. In addition, and in close connection with the previous point, we demonstrate the numerical dominance of the classical form factor over all others, except in the vicinity of the soft-gluon kinematics. The final upshot of these considerations is the emergence of a very compact description for the three-gluon vertex in general kinematics, which may simplify significantly nonperturbative applications involving this vertex.
	Address	[Aguilar, A. C.; 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	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:001117709800001			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5847
Permanent link to this record



	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	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	Horak, J.; Ihssen, F.; Papavassiliou, J.; Pawlowski, J.M.; Weber, A.; Wetterich, C.
	Title	Gluon condensates and effective gluon mass			Type	Journal Article
	Year	2022	Publication	Scipost Physics	Abbreviated Journal	SciPost Phys.
	Volume	13	Issue	2	Pages	042 - 40pp
	Keywords
	Abstract	Lattice simulations along with studies in continuum QCD indicate that non-perturbative quantum fluctuations lead to an infrared regularisation of the gluon propagator in covariant gauges in the form of an effective mass-like behaviour. In the present work we propose an analytic understanding of this phenomenon in terms of gluon condensation through a dynamical version of the Higgs mechanism, leading to the emergence of color condensates. Within the functional renormalisation group approach we compute the effective potential of covariantly constant field strengths, whose non-trivial minimum is related to the color condensates. In the physical case of an SU(3) gauge group this is an octet condensate. The value of the gluon mass obtained through this procedure compares very well to lattice results and the mass gap arising from alternative dynamical scenarios.
	Address	[Horak, Jan; Ihssen, Friederike; Pawlowski, Jan M.; Weber, Axel; Wetterich, Christof] Heidelberg Univ, Inst Theoret Phys, Philosophenweg 16, D-69120 Heidelberg, Germany
	Corporate Author				Thesis
	Publisher	Scipost Foundation	Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2542-4653	ISBN		Medium
	Area		Expedition		Conference
	Notes	WOS:000863121000008			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5379
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	Author	MoEDAL Collaboration (Acharya, B. et al); Mitsou, V.A.; Papavassiliou, J.; Ruiz de Austri, R.; Santra, A.; Vento, V.; Vives, O.
	Title	Search for magnetic monopoles produced via the Schwinger mechanism			Type	Journal Article
	Year	2022	Publication	Nature	Abbreviated Journal	Nature
	Volume	602	Issue	7895	Pages	63-67
	Keywords
	Abstract	Electrically charged particles can be created by the decay of strong enough electric fields, a phenomenon known as the Schwinger mechanism(1). By electromagnetic duality, a sufficiently strong magnetic field would similarly produce magnetic monopoles, if they exist(2). Magnetic monopoles are hypothetical fundamental particles that are predicted by several theories beyond the standard model(3-7) but have never been experimentally detected. Searching for the existence of magnetic monopoles via the Schwinger mechanism has not yet been attempted, but it is advantageous, owing to the possibility of calculating its rate through semi-classical techniques without perturbation theory, as well as that the production of the magnetic monopoles should be enhanced by their finite size(8,9) and strong coupling to photons(2,10). Here we present a search for magnetic monopole production by the Schwinger mechanism in Pb-Pb heavy ion collisions at the Large Hadron Collider, producing the strongest known magnetic fields in the current Universe(11). It was conducted by the MoEDAL experiment, whose trapping detectors were exposed to 0.235 per nanobarn, or approximately 1.8 x 10(9), of Pb-Pb collisions with 5.02-teraelectronvolt center-of-mass energy per collision in November 2018. A superconducting quantum interference device (SQUID) magnetometer scanned the trapping detectors of MoEDAL for the presence of magnetic charge, which would induce a persistent current in the SQUID. Magnetic monopoles with integer Dirac charges of 1, 2 and 3 and masses up to 75 gigaelectronvolts per speed of light squared were excluded by the analysis at the 95% confidence level. This provides a lower mass limit for finite-size magnetic monopoles from a collider search and greatly extends previous mass bounds.
	Address	[Acharya, B.; Alexandre, J.; Ellis, J. R.; Fairbairn, M.; Mavromatos, N. E.; Sakellariadou, M.; Sarkar, S.] Kings Coll London, Phys Dept, Theoret Particle Phys & Cosmol Grp, London, England
	Corporate Author				Thesis
	Publisher	Nature Portfolio	Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0028-0836	ISBN		Medium
	Area		Expedition		Conference
	Notes	WOS:000750429600019			Approved	no
	Is ISI	yes	International Collaboration	yes
	Call Number	IFIC @ pastor @			Serial	5191
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