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© Elsevier Science Bv. We thank Prof. A. Martínez Finkelshtein for useful conversations and for calling our attention to the work [20]. The financial support of the Ministerio de Ciencia e Innovación under project FIS2011-22566 is gratefully acknowledged., We apply the method we have described in a previous paper (2013) to determine the phase structure of asymptotic zero densities of the standard cubic model of non-Hermitian orthogonal polynomials. We provide a complete description of the two phases: the one cut phase and the two cut phase, and analyze the phase transition processes of the types: splitting of a cut, birth and death of a cut. (C) 2014 Elsevier B.V. All rights reserved., Ministerio de Ciencia e Innovacion, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©Elsevier Science BV. Erice School on Electromagnetic Probes and the Structure of Hadrons and Nuclei (1999. Erice, Italia). This work is partly supported by DGICYT, contract number PB 96-0753, By means of a coupled channel non-perturbative unitary approach, it is possible to extend the strong constrains of Chiral Perturbation Theory to higher energies. In particular, it is possible to reproduce the lowest lying resonances in mesonmeson scattering up to 1.2 GeV using the parameters of the O(p²) and O ( p^ 4 ) Chiral Lagrangian. The meson baryon sector can also be tackled along similar lines. We report on an update of these results showing some examples of photon induced reactions where the techniques have been recently applied., DGICYT, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2003 Elsevier Science B.V. All rights reserved., We present an equivalence theorem for the longitudinal components of the gauge bosons in a compactified five-dimensional extension of the Standard Model, whose spontaneous symmetry breaking is driven either by one Higgs in the bulk or by one on a brane or by both together. We also show some implications for the unitarity bounds on Higgs masses., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2005 Elsevier B.V. All rights reserved., A class of exact solutions of the dispersionless Toda hierarchy constrained by a string equation is obtained. These solutions represent deformations of analytic curves with a finite number of nonzero harmonic moments. The corresponding tau-functions are determined and the emergence of cusps is studied., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©Elsevier Science Bv. International Conference on Hadron Spectroscopy (hadron '99) (8. 1999. Beijing, República Popular China), By means of a coupled channel non-perturbative unitary approach, it is possible to extend the strong constrains of Chiral Perturbation Theory to higher energies. In particular, it is possible to reproduce the lowest lying resonances in meson-meson scattering up to 1.2 GeV using the parameters of the O (p²) and O (p⁴) Chiral Lagrangian. We report on an update of these results examining their possible relevance for meson spectroscopy, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©1997 Elsevier Science B.V. We should like to thank Allan Fordy and Kimio Ueno for making the reference [ 15] available to us., Darboux transformation is reconsidered for the supersymmetric KdV system. By iterating the Darboux transformation, a supersymmetric extension of the Crum transformation is obtained for the Manin-Radul SKdV equation, in doing so one gets Wronskian superdeterminant representations for the solutions. Particular examples provide us explicit supersymmetric extensions, super solitons, of the standard soliton of the KdV equation. The KdV soliton appears as the body of the super soliton., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©Elsevier Science Bv. J.R.P. thanks A. Galindo, A. González Arroyo and M.J. Herrero, for kindly providing information about Paco Ynduráin’s career and H. Leutwyler for his comments about the matching of the S0 wave., This talk is dedicated to the memory of Paco Yndurain, the original speaker in the conference. After a short account of his scientific career, we briefly review our ongoing collaboration to determine precisely the pi pi scattering amplitude including the most recent data by means of Forward Dispersion Relations and Roy Equations. A remarkable improvement in precision over the intermediate energy region is obtained by using once-subtracted Roy Equations in addition to the standard twice-subtracted ones., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2007 Elsevier B.V. This study was supported by grant PEI 1340-02, from the Universidad de Antofagasta, Chile, and UR 055 PALEOTROPIQUE, IRD, France. Support was also provided by IRD through the JEAI (Jeune Equipe Associée à l'IRD) program. We thank Freddy Rabasté and Keyla Majluf for their help in sampling and analytical support in nutrient and chlorophyll determinations. Special thanks to anonymous reviewers for their comments and significantly improving the manuscript., Physical-chemical parameters (temperature, salinity, dissolved oxygen, nutrients, and chlorophyll concentration) of surface waters were used to evaluate the influence of biological and physical processes over the metal concentrations (Cd, Ni, V, Mo, Mn, and Fe) in different periods of a normal annual cycle (June 2002 and April 2003), in Mejillones Bay (23 degrees S), one of northern Chile's strongest upwelling cells. Two points were sampled every 2 months, but statistical analysis of these parameters did not show any spatial differences in surface water composition (annual average) in this bay. The order of total and dissolved metals by abundance (annual mean) in the Mejillones Bay surface waters during the sampling period was Cd < Ni < Mn < Fe < V < Mo. The surface concentration of metals does not appear to be explained by anthropogenic inputs (at least not during the year of this work), and variability observed in this study appears to be natural. The lack of correlation between physical-chemical parameters and metals could indicate a more complex combination of factors acting on surface concentrations. Moreover, the mixture of water masses and the Oxygen Minimum Zone which characterizes the Mejillones bay should have an important influence on surface distribution of trace metals and can explain the high temporal variability observed in most of the metals analyzed in this work. A two-box conceptual model is proposed to suggest possible influences on metals in surface waters of this coastal ecosystem. (c) 2007 Elsevier B.V. All rights reserved., Universidad de Antofagasta, Chile, IRD, France, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2000 Elsevier Science B.V. All rights reserved. Q.P.L. should like to thank the Abdus Salam International Centre for the Theoretical Physics for hospitality and support. Q.P.L. is partially supported by the National Natural Science Foundation of China ( grant no. 19971094) . M.M. is partially supported by Comision Inter-ministerial de Ciencia y Tecnología PB98–0821., We construct Darboux transformations for the super-symmetric KP hierarchies of Manin-Radul and Jacobian types. We also consider the binary Darboux transformation for the hierarchies. The iterations of both type of Darboux transformations are briefly discussed., National Natural Science Foundation of China, Comision Inter-ministerial de Ciencia y Tecnología, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© Elsevier Science BV., We make a thermal analysis of the light scalar susceptibilities using SU(3)-chiral perturbation theory to one-loop order, taking into account the QCD source of isospin breaking (IB), i.e. corrections coming from m(u) not equal m(d). The value of the connected scalar susceptibility in the infrared regime, the one relevant when approaching chiral symmetry restoration, and below the critical temperature is found to be entirely dominated by the pi(0)-eta mixing, which leads to model-independent O(epsilon(0)) corrections, where epsilon similar to m(d) - m(u), in the combination chi(uu) - chi(ud) of flavour breaking susceptibilities. We also present preliminary results for the corrections to the real part of the pion self-energy at next-to-leading order in SU(2)chiral perturbation theory, taking into account electromagnetic interaction. The results for zero and finite temperature for the charged and neutral pions are given in terms of the 3-momentum of the external pion, and their difference is calculated to this order, stressing the fact that, at low and moderate temperature, the mass splitting M-pi +/- - M-pi 0 grows with temperature for, at least, non-zero charged pion mass running inside the loops., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2004 Elsevier B.V.. This work was partially supported by the DGI under grant No. BFM2002-02646 (A.G.-L.) and by a JSPS research fellowship (T.T.). One of us (T.T.) would like to thank A.A. Andrianov and M. Sato for useful discussions, as well as all the members of the Departamento de Física Teórica II, Universidad Complutense, for their kind hospitality during his stay., We construct a new family of N -fold supersymmetric systems which is referred to as “type B”. A higher-derivative representation of the N -fold supercharge for this new family is given by a deformation of the type A N -fold supercharge. By utilizing the same method as in the sl(2) construction of type A N -fold supersymmetry, we show that this family includes two of the quasi-solvable models of Post–Turbiner type, DGI, Spain, JSPS (TT), Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2004 Elsevier B.V. This work was partially supported by the Spanish DGI under grant No. BFM2002-02646. A.E. acknowledges the financial support of the Spanish Ministry of Education through an FPU scholarship, We construct new solvable rational and trigonometric spin models with near-neighbors interactions by an extension of the Dunkl operator formalism. In the trigonometric case we obtain a finite number of energy levels in the center of mass frame, while the rational models are shown to possess an equally spaced infinite algebraic spectrum. For the trigonometric and one of the rational models, the corresponding eigenfunctions are explicitly computed. We also study the scalar reductions of the models, some of which had already appeared in the literature, and compute their algebraic eigenfunctions in closed form. In the rational cases, for which only partial results were available, we give concise expressions of the eigenfunctions in terms of generalized Laguerre and Jacobi polynomials., DGI, Spain, Ministry of Education, Spain, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license. We are particularly thankful towards R.L. Jaffe for his participation at early stages of this work. The research was in part supported by the Spanish project FPA2011-27853-C02-02, DFG funds to the Sino-German CRC 110 “Symmetries and the Emergence of Structure in QCD”, and the EU I3HP “Study of Strongly Interacting Matter” under the Seventh Framework Program of the EU., We discuss in general terms pole trajectories of resonances coupling to a continuum channel as some strength parameter is varied. It is demonstrated that, regardless of the underlying dynamics, the trajectories of poles that couple to the continuum in a partial wave higher than s-wave are qualitatively the same, while in case of s-waves the pole trajectory can reveal important information on the internal structure of the resonance. In addition we show that only molecular (or extraordinary) states appear near thresholds naturally, while more compact structures need a significant fine tuning in the parameters. This study is of current relevance especially in strong interaction physics, since lattice QCD may be employed to deduce the pole trajectories for hadronic resonances as a function of the quark mass thus providing additional, new access to the structure of s-wave resonances., DFG, Seventh Framework Program of the EU, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3. We would like to than M.R. Pennington for several discussions. J.R.P. and J.N. are supported by the Spanish project FPA2011-27853-C02-02 and the Spanish network FIS2014-57026-REDT. J.N. acknowledges funding by the Fundación Ramón Areces. A.P.S. work is supported in part by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contracts DEAC05-06OR23177 and DE-FG0287ER40365., We apply a recently developed dispersive formalism to calculate the Regge trajectories of the f_2(1270), f´_ 2(1525) and K^∗(892) mesons. Trajectories are calculated, not fitted to a family of resonances. Assuming that these resonances can be treated in the elastic approximation, the only input are the pole position and residue of a resonance. In all three cases, the predicted Regge trajectories are almost real and linear, with slopes in agreement with the universal value of order 1 GeV_(−2). We also show how these results barely change when considering more than two subtractions in the dispersive formalism., Ministerio de Economía y Competitividad (MINECO), Fundacion Ramon Areces, U.S. Department of Energy, U.S. Department of Energy, Office of Science, Office of Nuclear Physics, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© Elsevier Science Bv. International Conference on Strong and Electroweak Matter (7. 2006. New York), We present recent results on finite temperature electromagnetic form factors and the electrical conductivity in a pion gas. The standard Chiral Perturbation Theory power counting needs to be modified for transport coefficients. We pay special attention to unitarity and to possible applications for dilepton and photon production., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©Elsevier Science BV., The string equation appearing in the double scaling limit of the Hermitian one–matrix model, which corresponds to a Galilean self–similar condition for the KdV hierarchy, is reformulated as a scaling self–similar condition for the Ur–KdV hierarchy. A non– scaling limit analysis of the one–matrix model has led to the complexified NLS hierarchy and a string equation. We show that this corresponds to the Galilean self– similarity condition for the AKNS hierarchy and also its equivalence to a scaling self– similar condition for the Heisenberg ferromagnet hierarchy., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© Elsevier Science Bv., We report on our present work, where by means of the Inverse Amplitude Method we unitarize the elastic pion nucleon scattering amplitudes of Heavy Barion Chiral Perturbation Theory at O(q(3)). We reproduce the scattering up to the inelastic thresholds including the Delta(1232) resonance. The fitted chiral constants are rather different from those obtained by fitting the extrapolated threshold parameters for the non-unitarized theory., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2001 Elsevier Science B.V. All rights reserved. The authors gratefully acknowledge the partial financial support of the DGES under grant PB98-0821. They would also like to thank A.M. Perelomov and O. Ragnisco for several useful conversations., A quantum Hamiltonian describing N particles on a line interacting pairwise via an elliptic function potential in the presence of an external field is introduced. For a discrete set of values of the strength of the external potential, it is shown that a finite number of eigenfunctions and eigenvalues of the model can be exactly. computed in an algebraic way., DGES, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©1997 Elsevier Science B.V., In this paper we present a vectorial Darboux transformation, in terms of ordinary determinants, for the supersymmetric extension of the Korteweg-de Vries equation proposed by Manin and Radul. It is shown how this transformation reduces to the Korteweg-de Vries equation. Sohton type solutions are constructed by dressing the vacuum and we present some relevant plots., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©1998 Elsevier Science B.V., We show how Ramond free neutral Fermi fields lead to a Ƭ-function theory of BKP type which describes iso-orthogonal deformations of systems of orthogonal curvilinear coordinates. We also provide a vertex operator representation for the classical Ribaucour transformation., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

The standard Metropolis Monte Carlo is used to simulate thermal magnetization decay in ensemble of interacting and non-interacting particles. The fitting of demagnetization curves to simple Neel Arrhenius model, using the volume distribution, suggests that in I non-interacting case one Monte Carlo step is proportional to a square root of time. The same dependence arises from the consideration of magnetic particle moving in the external potential according to Brownian dynamics. This constitutes the basis of the so-called Monte Carlo With quantified time step The analytical calculations show that the method works reasonably in the case of small-to-intermediate size barriers and for a high anisotropy system. The application of the method to magnetic recording media reveals qualitatively the same dependence on the exchange parameter as Obtained by kinetic Monte Carlo., Depto. de Análisis Matemático y Matemática Aplicada, Fac. de Ciencias Matemáticas, TRUE, pub

©1998 Elsevier Science B.V. All rights reserved., We reduce the vectorial binary Darboux transformation for the Manin-Radul supersymmetric KdV system in such a way that it preserves the Manin-Radul-Mathieu supersymmetric KdV equation reduction. Expressions in terms of bosonic Pfaffians are provided for transformed solutions and wave functions. We also consider the implications of these results for the supersymmetric sine-Gordon equation., Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

©2006 Elsevier B.V. Partially supported by MEC project FIS2005-00319, A scheme for solving quasiclassical-string equations is developed to prove that genus-zero hitham hierarchies describe the deformations of planar domains determined by rational conformal-maps. This property is applied in normal matrix models to show that deformations of simply-connected supports of eigenvalues under changes of coupling constants are governed by genus-zero Whitham hierarchies., Ministerio de Educación y Ciencia, Spain, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© 2022 The Authors Artículo escrito por más de 10 autores. Talent Scientific Research Program of College of Physics, Sichuan University, Grant No. 1082204112427; the Fostering Program in Disciplines Possessing Novel Features for Natural Science of Sichuan University, Grant No. 2020SCUNL209; 1000 Talent program of Sichuan province 2021; Xunta de Galicia (Centro singular de investigacion de Galicia accreditation 2019-2022); European Union ERDF, "Maria de Maeztu'' Units of Excellence program (MDM-2016-0692); Red Tematica Nacional de Astroparticulas (RED2018-102661-T); "la Caixa'' Foundation (ID 100010434); European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 847648, fellowship code LCF/BQ/PI21/11830030, and grant agreement No. 754510; Serbian Ministry of Education, Science and Technological Development Contract No. (451-03-9/2021-14/200124); FSR Incoming Postdoctoral Fellowship Ministry of Education, Science and Technological Development, Serbia (451-03-9/2021-14/200124); University of Rijeka grant (uniri-prirod-18-48); Croatian Science Foundation (HRZZ) project number IP-2016-06-9782; Villum Fonden (29405); DGA-FSE [2020-E2117R]; European Regional Development Fund through the Center of Excellence (TK133) "The Dark Side of the Universe''; European Regional Development Fund (ESIF/ERDF) and the Czech Ministry of Education, Youth and Sports (MSMT) [Project CoGraDS-CZ.02.1.01/0.0/0.0/15 003/0000437]; Blavatnik & Rothchild grants; Basque Government grant (IT-97916); Basque Foundation for Science (IKERBASQUE); ESA Prodex grants C4000120711, 4000132310; FNRS (Belgian Fund for Research); DGAPA-PAPIIT-UNAM [TA100122]; UNLP (X909); DICYT 042131GR (J.G.); Hungarian National Research Development and Innovation Office NKFIH (Grant No. 123996); FQXi; Swiss National Science Foundation (181461, 199307); Nederlandse Organisatie voor Wetenschappelijk Onderzoek -NWO (grant numbers 680-91-119, 15MV71, and sectorplan); Japan Soc, The exploration of the universe has recently entered a new era thanks to the multi-messenger paradigm, characterized by a continuous increase in the quantity and quality of experimental data that is obtained by the detection of the various cosmic messengers (photons, neutrinos, cosmic rays and gravitational waves) from numerous origins. They give us information about their sources in the universe and the properties of the intergalactic medium. Moreover, multi-messenger astronomy opens up the possibility to search for phenomenological signatures of quantum gravity. On the one hand, the most energetic events allow us to test our physical theories at energy regimes which are not directly accessible in accelerators; on the other hand, tiny effects in the propagation of very high energy particles could be amplified by cosmological distances. After decades of merely theoretical investigations, the possibility of obtaining phenomenological indications of Planck-scale effects is a revolutionary step in the quest for a quantum theory of gravity, but it requires cooperation between different communities of physicists (both theoretical and experimental). This review, prepared within the COST Action CA18108 "Quantum gravity phenomenology in the multi-messenger approach", is aimed at promoting this cooperation by giving a state-of-the art account of the interdisciplinary expertise that is needed in the effective search of quantum gravity footprints in the production, propagation and detection of cosmic messengers. (C) 2022 The Authors. Published by Elsevier B.V., Unión Europea. Horizonte 2020, Ministerio de Ciencia e Innovación (MICINN)/ FEDER MCIN/AEI/10.13039/501100011033/FEDER, Ministerio de Ciencia e Innovación (MICINN) MCIN/AEI/10.13039/501100011033, Ministerio de Ciencia e Innovación (MICINN), Unidad de Excelencia María de Maeztu (MICINN), Comunidad de Madrid, Centro de Excelencia Severo Ochoa, Croatian Science Foundation (HRZZ), Czech Ministry of Education, Youth and Sports (MŠMT), Hungarian National Research Development and Innovation Office (NKFIH), Swiss National Science Foundation, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Estonian Research Council, Swedish Research Council, Ministero dell’Istruzione, Universit‘a e della Ricerca (MIUR), Romanian Ministry of Research Innovation and Digitalization, Bundesministerium für Bildung und Forschung (BMBF), National Science Centre (Polonia), Research Council of Norway (RCN), Science and Technology Facilities Council (STFC), Fundação para a Ciência e a Tecnologia, Centre National de la Recherche Scientifique (CNRS), Gobierno Vasco, Generalitat Valenciana, Generalitat de Catalunya, Comunidad de Madrid, Junta de Andalucía, University of Rijeka, Universidad de Barcelona, Deutsche Forschungsgemeinschaft (DFG), Istituto Nazionale di Fisica Nucleare (INFN), Bulgarian NSF, Fundación La Caixa, Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© 2020 Elsevier Science Bv. We are indebted to Victor I. Afonso, Jose Beltran-Jimenez, Francisco Cabral, Joaquin Diaz-Alonso, Francisco S. N. Lobo, Sergei Odintsov, Emanuele Orazi, Diego Saez-Gomez, Jeremy Sakstein, and Hermano Velten for providing us with feedback and clarifications related to the contents of this work at different levels. In particular, we are deeply thankful to Adria Delhom for his effort in proofreading this entire work and still keeping friends with us. GJO is funded by the Ramon y Cajal, Spain contract RYC-2013-13019 (Spain). DRG is funded by the Atraccion de Talento Investigador programme of the Comunidad de Madrid (Spain) No. 2018-T1/TIC-10431, and acknowledges further support from the Ministerio de Ciencia, Innovacion y Universidades (Spain) project No. PID2019-108485GB-I00/AEI/10.13039/501100011033, and by the Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) research projects Nos. PTDC/FIS-OUT/29048/2017 and PTDC/FIS-PAR/31938/2017. AW is supported by the European Union through the ERDF CoE grant TK133 and by FAPES (Brazil). DRG and AW thank the Department of Physics and IFIC of the University of Valencia for their hospitality during different stages of the elaboration of this work. This work is supported by the Spanish project FIS2017-84440-C2-1P (MINECO/FEDER, EU), the project H2020-MSCA-RISE-2017 Grant FunFiCO-777740, the project SEJI/2017/042, Spain (Generalitat Valenciana), the Consolider Program CPANPHY-1205388, Spain, the Severo Ochoa grant SEV-2014-0398 (Spain) and the Edital 006/2018 PRONEX (FAPESQ-PB/CNPQ, Brazil) Grant No. 0015/2019. This article is based upon work from COST Actions CA15117 (Cosmology and Astrophysics Network for Theoretical Advances and Training Actions) and CA18108 (Quantum gravity phenomenology in the multi-messenger approach), supported by COST (European Cooperation in Science and Technology)., The understanding of stellar structure represents the crossroads of our theories of the nuclear force and the gravitational interaction under the most extreme conditions observably accessible. It provides a powerful probe of the strong field regime of General Relativity, and opens fruitful avenues for the exploration of new gravitational physics. The latter can be captured via modified theories of gravity, which modify the Einstein-Hilbert action of General Relativity and/or some of its principles. These theories typically change the Tolman-Oppenheimer-Volkoff equations of stellar's hydrostatic equilibrium, thus having a large impact on the astrophysical properties of the corresponding stars and opening a new window to constrain these theories with present and future observations of different types of stars. For relativistic stars, such as neutron stars, the uncertainty on the equation of state of matter at supranuclear densities intertwines with the new parameters coming from the modified gravity side, providing a whole new phenomenology for the typical predictions of stellar structure models, such as mass-radius relations, maximum masses, or moment of inertia. For non-relativistic stars, such as white, brown and red dwarfs, the weakening/strengthening of the gravitational force inside astrophysical bodies via the modified Newtonian (Poisson) equation may induce changes on the star's mass, radius, central density or luminosity, having an impact, for instance, in the Chandrasekhar's limit for white dwarfs, or in the minimum mass for stable hydrogen burning in high-mass brown dwarfs. This work aims to provide a broad overview of the main such results achieved in the recent literature for many such modified theories of gravity, by combining the results and constraints obtained from the analysis of relativistic and non-relativistic stars in different scenarios. Moreover, we will build a bridge between the efforts of the community working on different theories, formulat, Unión Europea. Horizonte 2020, Ministerio de Economía y Competitividad (MINECO)/FEDER, Ministerio de Ciencia, Innovación y Universidades (MICIU), Comunidad de Madrid, Generalitat Valenciana, Programa Ramón y Cajal, Fundação para a Ciência e a Tecnologia (FCT), Consejo Superior de Investigaciones Científicas (CSIC), Centros de Excelencia Severo Ochoa (MINECO), Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub

© 2020 The Author(s). C. B. is funded by the National Scientific and Technical Research Council (CONICET). AD and AJC are supported by a PhD contract of the program FPU 2015 (Spanish Ministry of Economy and Competitiveness) with references FPU15/05406 and FPU15/02864, respectively. GJO is funded by the Ramon y Cajal contract RYC-2013-13019 (Spain). DRG is funded by the Atraccion de Talento Investigadorprogramme of the Comunidad de Madrid No. 2018-T1/TIC-10431, and acknowledges support from the Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) research grants Nos. PTDC/FIS-OUT/29048/2017 and PTDC/FIS-PAR/31938/2017. Thiswork is supported by the Spanish projects FIS2017-84440-C2-1-P, FIS2014-57387-C3-1-P (MINECO/FEDER, EU) and i-LINK1215 (CSIC), the project H2020-MSCA-RISE-2017 Grant FunFiCO-777740, the project SEJI/2017/042 (Generalitat Valenciana), the Consolider Program CPANPHY-1205388, and the Severo Ochoa grant SEV2014-0398 (Spain). This article is based upon work from COST Action CA15117, supported by COST (European Cooperation in Science and Technology)., Projective invariance is a symmetry of the Palatini version of General Relativity which is not present in the metric formulation. The fact that the Riemann tensor changes nontrivially under projective transformations implies that, unlike in the usual metric approach, in the Palatini formulation this tensor is subject to a gauge freedom, which allows some ambiguities even in its scalar contractions. In this sense, we show that for the Schwarzschild solution there exists a projective gauge in which the (affine) Kretschmann scalar, K (R beta mu nu R alpha beta mu nu)-R-alpha, can be set to vanish everywhere. This puts forward that the divergence of curvature scalars may, in some cases, be avoided by a gauge transformation of the connection. (C) 2020 The Author(s). Published by Elsevier B.V., Unión Europea. H2020, Ministerio de Economía y Competitividad (MINECO)/FEDER, Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, Generalitat Valenciana, Consejo Superior de Investigaciones Científicas, Programa Ramón y Cajal, Centro de Excelencia Severo Ochoa, Fundação para a Ciência e a Tecnologia (FCT), Centro Nacional de Física de Partículas, Astropartículas y Nuclear (CPAN), Depto. de Física Teórica, Fac. de Ciencias Físicas, TRUE, pub