Anabalon, A., Canfora, F., Giacomini, A., & Oliva, J. (2011). Black holes with gravitational hair in higher dimensions. Phys. Rev. D, 84(8), 10 pp.
Abstract: A new class of vacuum black holes for the most general gravity theory leading to second order field equations in the metric in even dimensions is presented. These spacetimes are locally antide Sitter in the asymptotic region, and are characterized by a continuous parameter that does not enter in the conserve charges, nor it can be reabsorbed by a coordinate transformation: it is therefore a purely gravitational hair. The black holes are constructed as a warped product of a twodimensional spacetime, which resembles the rt plane of the BanadosTeitelboimZanelli black hole, times a warp factor multiplying the metric of a D – 2dimensional Euclidean base manifold, which is restricted by a scalar equation. It is shown that all the Noether charges vanish. Furthermore, this is consistent with the Euclidean action approach: even though the black hole has a finite temperature, both the entropy and the mass vanish. Interesting examples of base manifolds are given in eight dimensions which are products of Thurston geometries, giving then a nontrivial topology to the black hole horizon. The possibility of introducing a torsional hair for these solutions is also discussed.

Anabalon, A., Canfora, F., Giacomini, A., & Oliva, J. (2011). Gribov ambiguity in asymptotically AdS threedimensional gravity. Phys. Rev. D, 83(6), 7 pp.
Abstract: In this paper the zero modes of the de Donder gauge FaddeevPopov operator for threedimensional gravity with negative cosmological constant are analyzed. It is found that the AdS(3) vacuum produces (infinitely many) normalizable smooth zero modes of the FaddeevPopov operator. On the other hand, it is found that the BanadosTeitelboimZanelli black hole (including the zero mass black hole) does not generate zero modes. This differs from the usual Gribov problem in QCD where, close to the maximally symmetric vacuum, the FaddeevPopov determinant is positive definite while "far enough'' from the vacuum it can vanish. This suggests that the zero mass BanadosTeitelboimZanelli black hole could be a suitable ground state of threedimensional gravity with negative cosmological constant. Because of the kinematic origin of this result, it also applies for other covariant gravity theories in three dimensions with AdS(3) as maximally symmetric solution, such as new massive gravity and topologically massive gravity. The relevance of these results for supersymmetry breaking is pointed out.

Anabalon, A., Canfora, F., Giacomini, A., & Oliva, J. (2012). Black holes with primary hair in gauged N=8 supergravity. J. High Energy Phys., (6), 12 pp.
Abstract: In this paper, we analyze the static solutions for the U(1)(4) consistent truncation of the maximally supersymmetric gauged supergravity in four dimensions. Using a new parametrization of the known solutions it is shown that for fixed charges there exist three Possible black hole configurations according to the pattern of symmetry breaking of the (scalars sector of the) Lagrangian. Namely a black hole without scalar fields, a black hole with a primary hair and a black hole with a secondary hair respectively. This is the first, exact, example of a black hole with a primary scalar hair, where both the black hole and the scalar fields are regular on and outside the horizon. The configurations with secondary and primary hair can be interpreted as a spontaneous symmetry breaking of discrete permutation and reflection symmetries of the action. It is shown that there exist a triple point in the thermodynamic phase space where the three solution coexist. The corresponding phase transitions are discussed and the free energies are written explicitly as function of the thermodynamic coordinates in the uncharged case. In the charged case the free energies of the primary hair and the hairless black hole are also given as functions of the thermodynamic coordinates.

Canfora, F., Gomberoff, A., Oh, S. H., Rojas, F., & SalgadoRebolledo, P. (2019). Meronic EinsteinYangMills black hole in 5D and gravitational spin from isospin effect. J. High Energy Phys., (6), 32 pp.
Abstract: We construct an analytic black hole solution in SU(2) EinsteinYangMills theory in five dimensions supporting a Meron field. The gauge field is proportional to a pure gauge and has a nontrivial topological charge. The wouldbe singularity at the Meron core gets shielded from the exterior by the black hole horizon. The metric has only one integration constant, namely, its ADM mass, which is shown to be finite once an appropriate boundary term is added to the action. The thermodynamics is also worked out, and a firstorder phase transition, similar to the one occurring in the ReissnerNordstrom case is identified. We also show that the solution produces a spin from isospin effect, i.e., even though the theory is constructed out of bosons only, the combined system of a scalar field and this background may become fermionic. More specifically, we study scalar excitations in this purely bosonic background and find that the system describes fermionic degrees of freedom at spatial infinity. Finally, for the asymptotically AdS(5) case, we study its consequences in the context of the AdS/CFT correspondence.

Canfora, F., Gomez, A., Sorella, S. P., & Vercauteren, D. (2014). Study of YangMills.ChernSimons theory in presence of the Gribov horizon. Ann. Phys., 345, 166–177.
Abstract: The twopoint gauge correlation function in YangMillsChernSimons theory in three dimensional Euclidean space is analysed by taking into account the nonperturbative effects of the Gribov horizon. In this way, we are able to describe the confinement and deconfinement regimes, which naturally depend on the topological mass and on the gauge coupling constant of the theory. (C) 2014 Elsevier Inc. All rights reserved.

Canfora, F., Oh, S. H., & SalgadoRebolledo, P. (2017). Gravitational catalysis of merons in EinsteinYangMills theory. Phys. Rev. D, 96(8), 10 pp.
Abstract: We construct regular configurations of the EinsteinYangMills theory in various dimensions. The gauge field is of merontype: it is proportional to a pure gauge (with a suitable parameter lambda determined by the field equations). The corresponding smooth gauge transformation cannot be deformed continuously to the identity. In the threedimensional case we consider the inclusion of a ChernSimons term into the analysis, allowing lambda to be different from its usual value of 1/2. In four dimensions, the gravitating meron is a smooth Euclidean wormhole interpolating between different vacua of the theory. In five and higher dimensions smooth meronlike configurations can also be constructed by considering warped products of the threesphere and lowerdimensional Einstein manifolds. In all cases merons (which on flat spaces would be singular) become regular due to the coupling with general relativity. This effect is named “gravitational catalysis of merons”.

Canfora, F. E., Dudal, D., Justo, I. F., Pais, P., SalgadoRebolledo, P., Rosa, L., et al. (2017). Double nonperturbative gluon exchange: An update on the softPomeron contribution to pp scattering. Phys. Rev. C, 96(2), 8 pp.
Abstract: We employ a set of recent, theoretically motivated fits to nonperturbative unquenched gluon propagators to check on how far double gluon exchange can be used to describe the soft sector of pp scattering data (total and differential cross section). In particular, we use the refined GribovZwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwalltype gluon propagator (as motivated from DysonSchwinger equations) in conjunction with a perturbative quarkgluon vertex, next to a model based on the nonperturbative quarkgluon MarisTandy vertex, popular from BetheSalpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with older ISR and more recent TOTEM and ATLAS data. The lower the value of total energy root s, the better the results appear to be.
