Showing 1–50 of 86 results for author: Lessa, A

Freeze-in at all couplings

Authors: Andreas Goudelis, Andre Lessa, Lucas Magno Dantas Ramos, Thomas Reggio

Abstract: We perform a comprehensive analysis of a charged parent freeze-in dark matter model, focusing on scenarios where the Universe reheats to a temperature comparable to or lower than the mass scales of the theory. In such configurations, dark matter production is Boltzmann-suppressed, allowing for stronger couplings between dark matter and the Standard Model thermal bath while still reproducing the ob… ▽ More We perform a comprehensive analysis of a charged parent freeze-in dark matter model, focusing on scenarios where the Universe reheats to a temperature comparable to or lower than the mass scales of the theory. In such configurations, dark matter production is Boltzmann-suppressed, allowing for stronger couplings between dark matter and the Standard Model thermal bath while still reproducing the observed relic abundance. We emphasize the non-trivial interplay between the reheating temperature, the mediator and dark matter masses and the coupling strength. We show that tracking the number density evolution of both dark matter and the mediator is essential to obtain reliable predictions, including unexpected behaviors such as the mediator non-equilibration due to fast decays. Lastly, we explore the phenomenological implications of this scenario, updating constraints from LHC searches and lepton flavour-violating decays and highlighting the complementarity of these searches in probing the cosmologically viable parameter space. △ Less

Submitted 17 June, 2026; originally announced June 2026.

Comments: 25 pages, 9 figures

Local Strong-to-Weak Spontaneous Symmetry Breaking

Authors: Francisco Divi, Leonardo A. Lessa, Chong Wang

Abstract: We propose a local notion of strong-to-weak spontaneous symmetry breaking (SW-SSB), through a local one-point fidelity correlator. Compared with the previous definition in terms of a two-point fidelity correlator, our local formulation offers two key advantages: (1) it is easier to detect in large systems: for a system of size $N$ and with ${\rm poly}(N)$ amount of resources, one can detect the lo… ▽ More We propose a local notion of strong-to-weak spontaneous symmetry breaking (SW-SSB), through a local one-point fidelity correlator. Compared with the previous definition in terms of a two-point fidelity correlator, our local formulation offers two key advantages: (1) it is easier to detect in large systems: for a system of size $N$ and with ${\rm poly}(N)$ amount of resources, one can detect the local fidelity order up to volume scale $O(\log(N))$; and (2) the local SW-SSB order remains well defined in the thermodynamic limit, where the density matrix itself is not well defined. We show that key features of SW-SSB, including stability under finite-depth symmetric channels and long-range conditional mutual information, persist within this local framework. Our definition is conceptually analogous to local thermalization, as exemplified by pure states obeying the eigenstate thermalization hypothesis (ETH). For critical states, the local one-point fidelity correlator defines an interesting class of defect problems. We demonstrate the applicability of the local formulation through several concrete examples, and derive the universal scaling behavior of the local fidelity correlator in a range of critical systems, including ground states of conformal field theories as well as ballistic and diffusive free-fermion metals. △ Less

Submitted 27 May, 2026; originally announced May 2026.

Comments: 31 pages, 12 figures

Mixed-State Long-Range Entanglement from Dimensional Constraints

Authors: Leonardo A. Lessa, Tsung-Cheng Lu

Abstract: We present a new mechanism for long-range entanglement (LRE) in strongly symmetric many-body mixed states that does not rely on symmetry anomalies or long-range correlations. Our primary example is the maximally mixed state in the translation-invariant subspace on a one-dimensional ring. This state is LRE because translationally symmetric short-range entangled states span a subspace whose dimensio… ▽ More We present a new mechanism for long-range entanglement (LRE) in strongly symmetric many-body mixed states that does not rely on symmetry anomalies or long-range correlations. Our primary example is the maximally mixed state in the translation-invariant subspace on a one-dimensional ring. This state is LRE because translationally symmetric short-range entangled states span a subspace whose dimension grows only polynomially with system size, whereas the full translation-invariant subspace grows exponentially. We further discuss certain unconventional properties of this state, including logarithmically growing conditional mutual information, strong-to-weak spontaneous symmetry-breaking, and Rényi-index-dependent operator-space entanglement. We also construct a geometrically non-local Lindbladian to stabilize this state as the steady state. Our results identify dimensional mismatch as a novel route to LRE that is intrinsic to many-body mixed states. △ Less

Submitted 14 May, 2026; originally announced May 2026.

Comments: 27 pages, 2+8 figures

On the coverage of electroweak-inos within the pMSSM with SModelS -- a comparison with the ATLAS pMSSM study

Authors: Leo Constantin, Sabine Kraml, Andre Lessa, Theo Reymermier, Wolfgang Waltenberger

Abstract: The ATLAS collaboration has recently performed a vast scan of the phenomenological Minimal Supersymmetric Standard Model (pMSSM) with a focus on the electroweak-ino sector, and analysed how their Run 2 searches for electroweak production of supersymmetric (SUSY) particles constrain this dataset. All the SLHA files from the scan as well as the constraints from the eight individual searches consider… ▽ More The ATLAS collaboration has recently performed a vast scan of the phenomenological Minimal Supersymmetric Standard Model (pMSSM) with a focus on the electroweak-ino sector, and analysed how their Run 2 searches for electroweak production of supersymmetric (SUSY) particles constrain this dataset. All the SLHA files from the scan as well as the constraints from the eight individual searches considered by ATLAS were made publicly available. We use this material to study how well the ATLAS constraints can be reproduced with SModelS v3.0. Moreover, we explore how the picture changes when also including CMS results, and what can be gained by the statistical combination of analyses. Finally, we discuss the part of parameter space with light electroweak-inos that remains valid despite the stringent LHC limits. Our results underscore the need of a broad, multifaceted approach for maximising sensitivity and closing loopholes in the extensive SUSY parameter space. △ Less

Submitted 21 May, 2026; v1 submitted 16 December, 2025; originally announced December 2025.

Comments: 33 pages, 13 figures, 8 tables,version accepted by SciPost. All data and results presented in this work, together with jupyter notebooks to reproduce the paper plots, are publicly available at https://zenodo.org/records/17949022

Journal ref: SciPost Phys. 21, 002 (2026)

A Formalization of the Generalized Quantum Stein's Lemma in Lean

Authors: Alex Meiburg, Leonardo A. Lessa, Rodolfo R. Soldati

Abstract: The Generalized Quantum Stein's Lemma is a theorem in quantum hypothesis testing that provides an operational meaning to the relative entropy within the context of quantum resource theories. Its original proof was found to have a gap, which led to a search for a corrected proof. We formalize the proof presented in [Hayashi and Yamasaki (2024)] in the Lean interactive theorem prover. This is the mo… ▽ More The Generalized Quantum Stein's Lemma is a theorem in quantum hypothesis testing that provides an operational meaning to the relative entropy within the context of quantum resource theories. Its original proof was found to have a gap, which led to a search for a corrected proof. We formalize the proof presented in [Hayashi and Yamasaki (2024)] in the Lean interactive theorem prover. This is the most technically demanding theorem in physics with a computer-verified proof to date, building with a variety of intermediate results from topology, analysis, and operator algebra. In the process, we rectified minor imprecisions in [HY24]'s proof that formalization forces us to confront, and refine a more precise definition of quantum resource theory. Formalizing this theorem has ensured that our Lean-QuantumInfo library, which otherwise has begun to encompass a variety of topics from quantum information, includes a robust foundation suitable for a larger collaborative program of formalizing quantum theory more broadly. △ Less

Submitted 9 October, 2025; originally announced October 2025.

Comments: 20 pages, 2 figures, 7 code listings

MSC Class: 81P45 (Primary) 62M07; 68V20 (Secondary) ACM Class: F.4.1; H.1.1

Black holes in higher-derivative Weyl conformal gravity

Authors: Leandro A. Lessa, Caio F. B. Macedo, Manoel M. Ferreira Jr

Abstract: We obtain exact black hole solutions for static and spherically symmetric sources in a Weyl conformal gauge theory of gravity. We consider a quadratic gravitational action built from the Weyl tensor within a dilation geometry. In a post-Riemannian formulation, we derive a Weyl conformal action for a scalar-vector-tensor theory, where the scalar degree of freedom originates from the high-curvature… ▽ More We obtain exact black hole solutions for static and spherically symmetric sources in a Weyl conformal gauge theory of gravity. We consider a quadratic gravitational action built from the Weyl tensor within a dilation geometry. In a post-Riemannian formulation, we derive a Weyl conformal action for a scalar-vector-tensor theory, where the scalar degree of freedom originates from the high-curvature terms and the vectorial one stems from the Weyl non-metricity condition. Adopting a static, spherically symmetric geometry, the vacuum field equations for the gravitational, scalar, and Weyl fields are obtained. Under these conditions, we find a Mannheim-Kazanas-type black hole solution, whose Rindler acceleration term depends on the Weyl gauge coupling constant. Furthermore, we show that the original theory can recover the Einstein-Hilbert action with a positive cosmological constant plus a higher-derivative term with Horndeski-like terms through a spontaneous symmetry breaking triggered by the vacuum expectation value of the scalar field. The new solution in the theory without conformal symmetry presents new terms introduced by the residual Weyl symmetry corrections. We demonstrate that in a regime where the Planck mass suppresses the higher-derivative term, the Rindler term persists in the low-energy limit. △ Less

Submitted 25 September, 2025; originally announced September 2025.

Braneworlds in Einstein-Scalar-Gauss-Bonnet gravity

Authors: José Euclides G. Silva, Leandro A. Lessa, Roberto V. Maluf

Abstract: We explore the features of a thick braneworld model in five dimensions governed by a Einstein-Gauss-Bonnet gravity with a non-minimal coupling to a dynamical scalar field. We consider two possible scalar-GB coupling function $χ(φ)$, one parity-even and another parity-odd function of the scalar field $φ$. For both choices, the scalar-Gauss-Bonnet non-minimal coupling produces a warped asymptoticall… ▽ More We explore the features of a thick braneworld model in five dimensions governed by a Einstein-Gauss-Bonnet gravity with a non-minimal coupling to a dynamical scalar field. We consider two possible scalar-GB coupling function $χ(φ)$, one parity-even and another parity-odd function of the scalar field $φ$. For both choices, the scalar-Gauss-Bonnet non-minimal coupling produces a warped asymptotically $AdS_5$ spacetime even in the absence of a bulk cosmological constant. Outside the brane core, a negative cosmological constant is bounded by the scalar-GB coupling function. For a thick 3-brane configuration, we found solutions with localized brane energy density and pressure that dynamically produce a bulk cosmological constant. The corresponding scalar field solutions exhibit a non-topological (domain wall) behavior. In order to probe the 3-brane stability solution, we employed a perturbative analysis, by perturbing the thick brane solutions up to first-order. The Kaluza-Klein (KK) tensorial gravitational modes possess a localized massless mode and a tower of non-tachyonic diverging massive modes, what renders the solutions stable at least at the perturbative level. △ Less

Submitted 29 August, 2025; originally announced August 2025.

Symmetry enforces entanglement at high temperatures

Authors: Amir-Reza Negari, Leonardo A. Lessa, Subhayan Sahu

Abstract: Many-body quantum systems with local interactions undergo ``sudden death of entanglement" at high temperatures, whereby thermal states become classical mixtures of product states. We investigate whether symmetry constraints can prevent this phenomenon. We prove that strongly symmetric thermal states (canonical ensemble) of generic Hamiltonians with on-site Abelian symmetries remain entangled with… ▽ More Many-body quantum systems with local interactions undergo ``sudden death of entanglement" at high temperatures, whereby thermal states become classical mixtures of product states. We investigate whether symmetry constraints can prevent this phenomenon. We prove that strongly symmetric thermal states (canonical ensemble) of generic Hamiltonians with on-site Abelian symmetries remain entangled with non-zero entanglement negativity at arbitrarily high temperatures, under mild conditions on the symmetry actions and the charge sector of the strong symmetry. Our results extend to weakly symmetric thermal states (Gibbs ensemble) under superselection rules, which restrict state decompositions to be symmetric. In particular, we show that fermionic Gibbs states evade sudden death of entanglement and have persistent fermionic negativity at high temperatures, proving along the way some existing conjectures about fermionic entanglement. These findings demonstrate that global symmetry correlations can preserve quantum entanglement despite thermal decoherence, providing new insights into the interplay between symmetry and quantum information in thermal equilibrium. △ Less

Submitted 2 October, 2025; v1 submitted 27 August, 2025; originally announced August 2025.

Comments: 7+14 pages, 4 figures

Echoes and quasinormal modes of asymmetric black bounces

Authors: Alana C. L. Santos, Leandro A. Lessa, Roberto V. Maluf, Gonzalo J. Olmo

Abstract: We study quasinormal modes and echoes of symmetric and asymmetric black bounce solutions generated by anisotropic fluids within the framework of general relativity. We derive the effective potential governing massless scalar fields and compute the corresponding quasinormal mode spectra using three independent methods: sixth-order WKB, Pöschl-Teller and time-domain evolution. Our results show that… ▽ More We study quasinormal modes and echoes of symmetric and asymmetric black bounce solutions generated by anisotropic fluids within the framework of general relativity. We derive the effective potential governing massless scalar fields and compute the corresponding quasinormal mode spectra using three independent methods: sixth-order WKB, Pöschl-Teller and time-domain evolution. Our results show that symmetric black bounce configurations with horizons yield a standard single-barrier potential, while horizonless solutions may exhibit multiple potential barriers that generate gravitational wave echoes. These echoes are sensitive to model parameters such as the fluid energy density and the regularizing parameter $a$ that defines the minimal $2$-sphere. The asymmetric models considered recover the Reissner-Nordström solution in their external region but can be bounded or unbounded in the inside, depending on the sign of a parameter. Both cases have similar qualitative properties as far as wave emission is concerned but show no echoes. This makes it very difficult to distinguish them from standard Reissner-Nordström configurations. △ Less

Submitted 14 August, 2025; originally announced August 2025.

Comments: 26 pages, 9 figures, 2 tables

Journal ref: JCAP04(2026)010

Non-minimal matter sector couplings in Lorentz-violating gravity: Self-consistent traversable wormholes and quasinormal modes

Authors: Renan B. Magalhães, Leandro A. Lessa, Rodolfo Casana

Abstract: The anisotropies induced by Lorentz-violating fields pose significant challenges for the search for compact objects in non-vacuum environments. In this work, nevertheless, we demonstrate that introducing couplings between Lorentz-violating fields and matter allows a remarkable class of spacetimes: traversable wormholes. Specifically, we consider additional couplings in the Lagrangian of a phantom… ▽ More The anisotropies induced by Lorentz-violating fields pose significant challenges for the search for compact objects in non-vacuum environments. In this work, nevertheless, we demonstrate that introducing couplings between Lorentz-violating fields and matter allows a remarkable class of spacetimes: traversable wormholes. Specifically, we consider additional couplings in the Lagrangian of a phantom scalar field and derive Ellis-Bronnikov spacetime analogs in a Lorentz-violating scenario where both a vector field and an antisymmetric rank-2 tensor field spontaneously acquire non-zero vacuum expectation values. Despite the distinct nature of these fields, their non-zero vacuum expectation values contribute additively to the overall effect on the phantom distribution and on the resulting line element. Moreover, to probe the effects of the Lorentz violation in these spacetimes, we consider scalar perturbations lying in these spacetimes either coupled to the Lorentz-violating fields or minimally coupled to the metric. Notably, the additional Lorentz-violating couplings can alter scalar field dynamics so that perturbations propagate as if in a General Relativity background, thereby allowing for some traits of Lorentz violation to remain hidden. We compute the quasinormal mode spectra of these perturbations using three methods: direct integration, the 6th-order WKB approximation, and the Prony method, finding strong agreement among the results. △ Less

Submitted 12 June, 2026; v1 submitted 3 July, 2025; originally announced July 2025.

Journal ref: Phys. Rev. D 113, 124018 (2026)

Mixed-state phases from local reversibility

Authors: Shengqi Sang, Leonardo A. Lessa, Roger S. K. Mong, Tarun Grover, Chong Wang, Timothy H. Hsieh

Abstract: We propose a refined definition of mixed-state phase equivalence based on locally reversible channel circuits. We show that such circuits preserve topological degeneracy and the locality of all operators including both strong and weak symmetries. Under a locally reversible channel, weak unitary symmetries are locally dressed into channel symmetries, a new generalization of symmetry for open quantu… ▽ More We propose a refined definition of mixed-state phase equivalence based on locally reversible channel circuits. We show that such circuits preserve topological degeneracy and the locality of all operators including both strong and weak symmetries. Under a locally reversible channel, weak unitary symmetries are locally dressed into channel symmetries, a new generalization of symmetry for open quantum systems. For abelian higher-form symmetries, we show the refined definition preserves anomalies and spontaneous breaking of such symmetries within a phase. As a primary example, a two-dimensional classical loop ensemble is trivial under the previously adopted definition of mixed-state phases. However, it has non-trivial topological degeneracy arising from a mutual anomaly between strong and weak 1-form symmetries, and our results show that it is not connected to a trivial state via locally reversible channel circuits. △ Less

Submitted 25 July, 2025; v1 submitted 2 July, 2025; originally announced July 2025.

SUSY meets SMEFT: Complete one-loop matching of the general MSSM

Authors: Sabine Kraml, Andre Lessa, Suraj Prakash, Felix Wilsch

Abstract: We present the complete one-loop matching of the Minimal Supersymmetric Standard Model (MSSM) onto the Standard Model Effective Field Theory (SMEFT), considering the most general case for the MSSM with conserved $R$-parity, which has 124 free parameters. The matching is performed with the Matchete package, which integrates out all superpartners at once with non-degenerate masses, while also retain… ▽ More We present the complete one-loop matching of the Minimal Supersymmetric Standard Model (MSSM) onto the Standard Model Effective Field Theory (SMEFT), considering the most general case for the MSSM with conserved $R$-parity, which has 124 free parameters. The matching is performed with the Matchete package, which integrates out all superpartners at once with non-degenerate masses, while also retaining the most general flavor structure. Our results include all correlations among the different SMEFT Wilson coefficients that are governed by supersymmetry and thus provide a basis for future systematic and global studies of the MSSM parameter space employing EFT methods. A detailed discussion is provided on the treatment of the Higgs sector and electroweak symmetry breaking, along with the reduction of redundant operators in the EFT Lagrangian to the Warsaw basis. Furthermore, we validate against existing results in the literature and present a minimal phenomenological example. As an alternative low-energy scenario, we also provide the complete one-loop matching of the MSSM onto the two-Higgs-doublet-model EFT, where the second Higgs doublet is retained in the infrared spectrum. Extensive auxiliary material, including the code utilized for the matching, is available on GitHub. △ Less

Submitted 6 February, 2026; v1 submitted 5 June, 2025; originally announced June 2025.

Comments: 63 pages, 4 tables, 3 figures, auxiliary material available on GitHub: https://github.com/BSM-EFT/MSSM-to-SMEFT, this version matches the journal version and adds DR-MS scheme conversion and 2HDM-EFT matching

Report number: TTK-25-14, P3H-25-036

Journal ref: JHEP 04 (2026) 028

Wormholes in Lorentz-violating gravity

Authors: Renan B. Magalhães, Leandro A. Lessa, Manoel M. Ferreira Jr

Abstract: We investigate the possibility of obtaining traversable wormholes supported by phantom scalar fields in Lorentz-violating gravity with an antisymmetric rank-2 tensor with a non-zero vacuum expectation value non-minimally coupled to the curvature tensor. This Lorentz violation framework shows to be a suitable scenario to search for wormhole solutions in the presence of Lorentz violation, since it i… ▽ More We investigate the possibility of obtaining traversable wormholes supported by phantom scalar fields in Lorentz-violating gravity with an antisymmetric rank-2 tensor with a non-zero vacuum expectation value non-minimally coupled to the curvature tensor. This Lorentz violation framework shows to be a suitable scenario to search for wormhole solutions in the presence of Lorentz violation, since it introduces mild constraints on the areal radius. The vacuum expectation value of the antisymmetric rank-2 tensor, nonetheless, imposes constraints on the lapse function. As a consequence, under the vacuum configuration adopted, the allowed lapse functions can be either constant, linear or quadratic, depending on the self-interaction potential that drives the spontaneous breaking of the Lorentz symmetry. Thus, we find the Ellis-Bronnikov counterpart in this Lorentz-violating scenario as well as Lorentz-violating wormholes with a Rindler-type acceleration and an effective cosmological constant. Properties of these wormholes, such as their non-flat asymptotics, are investigated. △ Less

Submitted 12 May, 2025; originally announced May 2025.

On the self-consistency of compact objects in Lorentz-violating gravity theories

Authors: Leandro A. Lessa, Renan B. Magalhães, Manoel M. Ferreira Junior

Abstract: Self-consistent solutions in Lorentz-violating gravity theories require the simultaneous satisfaction of: (i) the corresponding Einstein field equations, (ii) the matter field equations, and (iii) the Lorentz-violating field equations. In vacuum states, the dynamics of Lorentz-violating tensor fields may reduce to geometric constraints, potentially precluding entire classes of compact objects. The… ▽ More Self-consistent solutions in Lorentz-violating gravity theories require the simultaneous satisfaction of: (i) the corresponding Einstein field equations, (ii) the matter field equations, and (iii) the Lorentz-violating field equations. In vacuum states, the dynamics of Lorentz-violating tensor fields may reduce to geometric constraints, potentially precluding entire classes of compact objects. These constraints are crucial for ensuring physical consistency in Lorentz-violating frameworks, as they eliminate metric families incompatible with the anisotropies induced by spontaneous Lorentz symmetry breaking. We investigate the criteria governing the emergence of these geometric constraints and analyze their consequences. Our analysis establishes a consistency framework for evaluating compact objects in these theories, demonstrating that several previously reported solutions in Lorentz-violating gravity models are physically inadmissible. △ Less

Submitted 9 September, 2025; v1 submitted 2 May, 2025; originally announced May 2025.

Comments: Accepted: Physical Review D

Brazilian Report on Dark Matter 2024

Authors: I. F. M. Albuquerque, J. Alcaniz, A. Alves, J. Amaral, C. Bonifazi, H. A. Borges, S. Carneiro, L. Casarini, D. Cogollo, A. G. Dias, G. C. Dorsch, A. Esmaili, G. Gil da Silveira, C. Gobel, V. P. Gonçalves, A. S. Jesus, D. Hadjimichef, P. C. de Holanda, R. F. L. Holanda, E. Kemp, A. Lessa, A. Machado, M. V T. Machado, M. Makler, V. Marra , et al. (29 additional authors not shown)

Abstract: One of the key scientific objectives for the next decade is to uncover the nature of dark matter (DM). We should continue prioritizing targets such as weakly-interacting massive particles (WIMPs), Axions, and other low-mass dark matter candidates to improve our chances of achieving it. A varied and ongoing portfolio of experiments spanning different scales and detection methods is essential to max… ▽ More One of the key scientific objectives for the next decade is to uncover the nature of dark matter (DM). We should continue prioritizing targets such as weakly-interacting massive particles (WIMPs), Axions, and other low-mass dark matter candidates to improve our chances of achieving it. A varied and ongoing portfolio of experiments spanning different scales and detection methods is essential to maximize our chances of discovering its composition. This report paper provides an updated overview of the Brazilian community's activities in dark matter and dark sector physics over the past years with a view for the future. It underscores the ongoing need for financial support for Brazilian groups actively engaged in experimental research to sustain the Brazilian involvement in the global search for dark matter particles △ Less

Submitted 8 May, 2025; v1 submitted 22 April, 2025; originally announced April 2025.

Comments: Editor-Convener: Farinaldo Queiroz. Report for the Latin American Association for High Energy, Cosmology and Astroparticle Physics

t-channel dark matter at the LHC -- a whitepaper

Authors: Chiara Arina, Benjamin Fuks, Luca Panizzi, Michael J. Baker, Alan S. Cornell, Jan Heisig, Benedikt Maier, Rute Pedro, Dominique Trischuk, Diyar Agin, Alexandre Arbey, Giorgio Arcadi, Emanuele Bagnaschi, Kehang Bai, Disha Bhatia, Mathias Becker, Alexander Belyaev, Ferdinand Benoit, Monika Blanke, Jackson Burzynski, Jonathan M. Butterworth, Antimo Cagnotta, Lorenzo Calibbi, Linda M. Carpenter, Xabier Cid Vidal , et al. (45 additional authors not shown)

Abstract: This report, summarising work achieved in the context of the LHC Dark Matter Working Group, investigates the phenomenology of $t$-channel dark matter models, spanning minimal setups with a single dark matter candidate and mediator to more complex constructions closer to UV-complete models. For each considered class of models, we examine collider, cosmological and astrophysical implications. In add… ▽ More This report, summarising work achieved in the context of the LHC Dark Matter Working Group, investigates the phenomenology of $t$-channel dark matter models, spanning minimal setups with a single dark matter candidate and mediator to more complex constructions closer to UV-complete models. For each considered class of models, we examine collider, cosmological and astrophysical implications. In addition, we explore scenarios with either promptly decaying or long-lived particles, as well as featuring diverse dark matter production mechanisms in the early universe. By providing a unified analysis framework, numerical tools and guidelines, this work aims to support future experimental and theoretical efforts in exploring $t$-channel dark matter models at colliders and in cosmology. △ Less

Submitted 14 September, 2025; v1 submitted 14 April, 2025; originally announced April 2025.

Comments: 101 pages, 55 figures; report of the LHC Dark Matter Working Group on t-channel dark matter models; version accepted by EPJC

Report number: CERN-LPCC-2025-001, IRMP-CP3-25-07, TTK-25-07

Journal ref: Eur.Phys.J.C 85 (2025) 975

Reinterpretation and preservation of data and analyses in HEP

Authors: Jon Butterworth, Sabine Kraml, Harrison Prosper, Andy Buckley, Louie Corpe, Cristinel Diaconu, Mark Goodsell, Philippe Gras, Martin Habedank, Clemens Lange, Kati Lassila-Perini, André Lessa, Rakhi Mahbubani, Judita Mamužić, Zach Marshall, Thomas McCauley, Humberto Reyes-Gonzalez, Krzysztof Rolbiecki, Sezen Sekmen, Giordon Stark, Graeme Watt, Jonas Würzinger, Shehu AbdusSalam, Aytul Adiguzel, Amine Ahriche , et al. (123 additional authors not shown)

Abstract: Data from particle physics experiments are unique and are often the result of a very large investment of resources. Given the potential scientific impact of these data, which goes far beyond the immediate priorities of the experimental collaborations that obtain them, it is imperative that the collaborations and the wider particle physics community publish and preserve sufficient information to en… ▽ More Data from particle physics experiments are unique and are often the result of a very large investment of resources. Given the potential scientific impact of these data, which goes far beyond the immediate priorities of the experimental collaborations that obtain them, it is imperative that the collaborations and the wider particle physics community publish and preserve sufficient information to ensure that this impact can be realised, now and into the future. The information to be published and preserved includes the algorithms, statistical information, simulations and the recorded data. This publication and preservation requires significant resources, and should be a strategic priority with commensurate planning and resource allocation from the earliest stages of future facilities and experiments. △ Less

Submitted 31 March, 2025; originally announced April 2025.

Comments: 10+9 pages, 4 figures; submitted to the European Strategy for Particle Physics Update 2026

Report number: CERN-LPCC-2025-002

Brazilian input to the European Strategy for Particle Physics Update

Authors: U. de Freitas Carneiro da Graça, G. Gil da Silveira, C. Jahnke, A. Lessa, H. Malbouisson, E. E. Purcino de Souza, M. S. Rangel, T. R. Fernandez Perez Tomei, A. Vilela Pereira, J. Citadini, M. F. A. Brito, S. Fonseca De Souza, C. Hensel, E. Silva Junior, L. de Paula

Abstract: The Brazilian High-Energy Physics (HEP) community has expanded remarkably since its first involvement at CERN and Fermilab in the 1980s. Its recent organization under the Brazilian Network for High-Energy Physics (RENAFAE), since 2008, has further strengthened its scientific and technological goals, particularly in detector instrumentation, computing, and industry partnerships. In 2024, Brazil bec… ▽ More The Brazilian High-Energy Physics (HEP) community has expanded remarkably since its first involvement at CERN and Fermilab in the 1980s. Its recent organization under the Brazilian Network for High-Energy Physics (RENAFAE), since 2008, has further strengthened its scientific and technological goals, particularly in detector instrumentation, computing, and industry partnerships. In 2024, Brazil became an Associate Member State of CERN, opening new opportunities for deeper engagement in accelerator and detector R&D. This input to the 2026 update of the European Strategy for Particle Physics highlights Brazil's current participation in LHC experiments as well as ongoing developments in detector and accelerator technology, and details the community's view towards future colliders. The potential for expanded scientific and industrial collaborations between Brazil and CERN is also discussed. △ Less

Submitted 23 December, 2025; v1 submitted 31 March, 2025; originally announced March 2025.

Comments: Submitted to the European Strategy for Particle Physics 2026 Update

Higher-form anomaly and long-range entanglement of mixed states

Authors: Leonardo A. Lessa, Shengqi Sang, Tsung-Cheng Lu, Timothy H. Hsieh, Chong Wang

Abstract: In open quantum systems, we directly relate anomalies of higher-form symmetries to the long-range entanglement of any mixed state with such symmetries. First, we define equivalence classes of long-range entanglement in mixed states via stochastic local channels (SLCs), which effectively ``mod out'' any classical correlations and thus distinguish phases by differences in long-range quantum correlat… ▽ More In open quantum systems, we directly relate anomalies of higher-form symmetries to the long-range entanglement of any mixed state with such symmetries. First, we define equivalence classes of long-range entanglement in mixed states via stochastic local channels (SLCs), which effectively ``mod out'' any classical correlations and thus distinguish phases by differences in long-range quantum correlations only. It is then shown that strong symmetries of a mixed state and their anomalies (non-trivial braiding and self-statistics) are intrinsic features of the entire phase of matter. For that, a general procedure of symmetry pullback for strong symmetries is introduced, whereby symmetries of the output state of an SLC are dressed into symmetries of the input state, with their anomaly relation preserved. This allows us to prove that states in (2+1)-D with anomalous strong 1-form symmetries exhibit long-range bipartite entanglement, and to establish a lower bound for their topological entanglement of formation, a mixed-state generalization of topological entanglement entropy. For concreteness, we apply this formalism to the toric code under Pauli-X and Z dephasing noise, as well as under ZX decoherence, which gives rise to the recently discovered intrinsically mixed-state topological order. Finally, we conjecture a connection between higher-form anomalies and long-range multipartite entanglement for mixed states in higher dimensions. △ Less

Submitted 17 March, 2025; originally announced March 2025.

Comments: 29 pages, 10+1 figures

On the Structure of Black Bounces Sourced by Anisotropic Fluids

Authors: L. A. Lessa, G. J. Olmo

Abstract: The field equations of static, spherically symmetric geometries generated by anisotropic fluids is investigated with the aim of better understanding the relation between the matter and the emergence of minimal area throats, like in wormhole and black bounce scenarios. Imposing some simplifying restrictions on the matter, which amounts to considering nonlinear electromagnetic sources, we find analy… ▽ More The field equations of static, spherically symmetric geometries generated by anisotropic fluids is investigated with the aim of better understanding the relation between the matter and the emergence of minimal area throats, like in wormhole and black bounce scenarios. Imposing some simplifying restrictions on the matter, which amounts to considering nonlinear electromagnetic sources, we find analytical expressions that allow one to design the type of sought geometries. We illustrate our analysis with several examples, including an asymmetric, bounded black bounce spacetime which reproduces the standard Reissner-Nordstrom geometry on the outside all the way down to the throat. △ Less

Submitted 6 December, 2024; originally announced December 2024.

Journal ref: JCAP03(2025)019

SModelS v3: Going Beyond Z2 Topologies

Authors: Mohammad Mahdi Altakach, Sabine Kraml, Andre Lessa, Sahana Narasimha, Timothée Pascal, Camila Ramos, Yoxara Villamizar, Wolfgang Waltenberger

Abstract: SModelS is a public tool for fast reinterpretation of LHC searches for new physics based on a large database of simplified model results. While previous versions were limited to models with a Z2-type symmetry, such as R-parity conserving supersymmetry, version 3 can now handle arbitrary signal topologies. To this end, the tool was fully restructured and now relies on a graph-based description of s… ▽ More SModelS is a public tool for fast reinterpretation of LHC searches for new physics based on a large database of simplified model results. While previous versions were limited to models with a Z2-type symmetry, such as R-parity conserving supersymmetry, version 3 can now handle arbitrary signal topologies. To this end, the tool was fully restructured and now relies on a graph-based description of simplified model topologies. In this work, we present the main conceptual changes and novel features of SModelS v3, together with the inclusion of new experimental searches for resonant production of spin-1 and spin-0 mediators with decays to quarks or to dark matter. Applying these results to a model containing two mediators, we discuss the interplay of resonance and missing energy searches, and the model's coverage by the currently available simplified model results. △ Less

Submitted 13 November, 2024; v1 submitted 19 September, 2024; originally announced September 2024.

Comments: 38 pages, 21 figures, 5 tables. Version accepted for publication in JHEP. SModelS v3 is available at https://smodels.github.io/ . The data and code used to produce the results in section 5 are available at https://zenodo.org/doi/10.5281/zenodo.13772537

Universal New Physics Latent Space

Authors: Anna Hallin, Gregor Kasieczka, Sabine Kraml, André Lessa, Louis Moureaux, Tore von Schwartz, David Shih

Abstract: We develop a machine learning method for mapping data originating from both Standard Model processes and various theories beyond the Standard Model into a unified representation (latent) space while conserving information about the relationship between the underlying theories. We apply our method to three examples of new physics at the LHC of increasing complexity, showing that models can be clust… ▽ More We develop a machine learning method for mapping data originating from both Standard Model processes and various theories beyond the Standard Model into a unified representation (latent) space while conserving information about the relationship between the underlying theories. We apply our method to three examples of new physics at the LHC of increasing complexity, showing that models can be clustered according to their LHC phenomenology: different models are mapped to distinct regions in latent space, while indistinguishable models are mapped to the same region. This opens interesting new avenues on several fronts, such as model discrimination, selection of representative benchmark scenarios, and identifying gaps in the coverage of model space. △ Less

Submitted 22 January, 2025; v1 submitted 29 July, 2024; originally announced July 2024.

Comments: 25 pages, 17 figures

Journal ref: Phys. Rev. D 111, 016006 (2025)

Black string solutions in Lifshitz spacetime

Authors: L. A. Lessa, J. E. G. Silva, J. Furtado

Abstract: In this paper we study black string solutions considering the Lifshitz anisotropic scaling. We have shown that a new class of asymptotically Lifshitz solutions can be generated by an Einstein-Maxwell-Dilaton theory with a cosmological constant. In the limit where we recover conformal scale invariance, we retrieve the usual black string solution. Furthermore, we demonstrated that to incorporate the… ▽ More In this paper we study black string solutions considering the Lifshitz anisotropic scaling. We have shown that a new class of asymptotically Lifshitz solutions can be generated by an Einstein-Maxwell-Dilaton theory with a cosmological constant. In the limit where we recover conformal scale invariance, we retrieve the usual black string solution. Furthermore, we demonstrated that to incorporate the effects of electric charge in the black string, at least two independent gauge fields coupled to the dilaton field are necessary. The charged black string solution exhibits new horizons that depend on the potential in Lifshitz exponent $z$. The stability of these new solutions is investigated through the thermodynamic analysis of the charged black string. The temperature, entropy, and heat capacity indicate that these modified black strings are thermodynamically stable. △ Less

Submitted 14 June, 2024; originally announced June 2024.

Symmetry enforced entanglement in maximally mixed states

Authors: Amin Moharramipour, Leonardo A. Lessa, Chong Wang, Timothy H. Hsieh, Subhayan Sahu

Abstract: Entanglement in quantum many-body systems is typically fragile to interactions with the environment. Generic unital quantum channels, for example, have the maximally mixed state with no entanglement as their unique steady state. However, we find that for a unital quantum channel that is `strongly symmetric', i.e. it preserves a global on-site symmetry, the maximally mixed steady state in certain s… ▽ More Entanglement in quantum many-body systems is typically fragile to interactions with the environment. Generic unital quantum channels, for example, have the maximally mixed state with no entanglement as their unique steady state. However, we find that for a unital quantum channel that is `strongly symmetric', i.e. it preserves a global on-site symmetry, the maximally mixed steady state in certain symmetry sectors can be highly entangled. For a given symmetry, we analyze the entanglement and correlations of the maximally mixed state in the invariant sector (MMIS), and show that the entanglement of formation and distillation are exactly computable and equal for any bipartition. For all Abelian symmetries, the MMIS is separable, and for all non-Abelian symmetries, the MMIS is entangled. Remarkably, for non-Abelian continuous symmetries described by compact semisimple Lie groups (e.g. $SU(2)$), the bipartite entanglement of formation for the MMIS scales logarithmically $\sim \log N$ with the number of qudits $N$. △ Less

Submitted 13 December, 2024; v1 submitted 12 June, 2024; originally announced June 2024.

Comments: 17+8 pages, 7 figures

Journal ref: PRX Quantum 5, 040336 (2024)

Strong-to-Weak Spontaneous Symmetry Breaking in Mixed Quantum States

Authors: Leonardo A. Lessa, Ruochen Ma, Jian-Hao Zhang, Zhen Bi, Meng Cheng, Chong Wang

Abstract: Symmetry in mixed quantum states can manifest in two distinct forms: strong symmetry, where each individual pure state in the quantum ensemble is symmetric with the same charge, and weak symmetry, which applies only to the entire ensemble. This paper explores a novel type of spontaneous symmetry breaking (SSB) where a strong symmetry is broken to a weak one. While the SSB of a weak symmetry is mea… ▽ More Symmetry in mixed quantum states can manifest in two distinct forms: strong symmetry, where each individual pure state in the quantum ensemble is symmetric with the same charge, and weak symmetry, which applies only to the entire ensemble. This paper explores a novel type of spontaneous symmetry breaking (SSB) where a strong symmetry is broken to a weak one. While the SSB of a weak symmetry is measured by the long-ranged two-point correlation function, the strong-to-weak SSB (SW-SSB) is measured by the fidelity correlator. We prove that SW-SSB is a universal property of mixed-state quantum phases, in the sense that the phenomenon of SW-SSB is robust against symmetric low-depth local quantum channels. We also show that the symmetry breaking is "spontaneous" in the sense that the effect of a local symmetry-breaking measurement cannot be recovered locally. We argue that a thermal state at a nonzero temperature in the canonical ensemble (with fixed symmetry charge) should have spontaneously broken strong symmetry. Additionally, we study non-thermal scenarios where decoherence induces SW-SSB, leading to phase transitions described by classical statistical models with bond randomness. In particular, the SW-SSB transition of a decohered Ising model can be viewed as the "ungauged" version of the celebrated toric code decodability transition. We confirm that, in the decohered Ising model, the SW-SSB transition defined by the fidelity correlator is the only physical transition in terms of channel recoverability. We also comment on other (inequivalent) definitions of SW-SSB, through correlation functions with higher Renyi indices. △ Less

Submitted 17 November, 2024; v1 submitted 6 May, 2024; originally announced May 2024.

Comments: 17+6 pages, 4 figures

Journal ref: PRX Quantum 6, 010344 (2025)

Probing conversion-driven freeze-out at the LHC

Authors: Jan Heisig, Andre Lessa, Lucas Magno D. Ramos

Abstract: Conversion-driven freeze-out is an appealing mechanism to explain the observed relic density while naturally accommodating the null-results from direct and indirect detection due to a very weak dark matter coupling. Interestingly, the scenario predicts long-lived particles decaying into dark matter with lifetimes favorably coinciding with the range that can be resolved at the LHC. However, the sma… ▽ More Conversion-driven freeze-out is an appealing mechanism to explain the observed relic density while naturally accommodating the null-results from direct and indirect detection due to a very weak dark matter coupling. Interestingly, the scenario predicts long-lived particles decaying into dark matter with lifetimes favorably coinciding with the range that can be resolved at the LHC. However, the small mass splitting between the long-lived particle and dark matter renders the visible decay products soft, challenging current search strategies. We consider four different classes of searches covering the entire range of lifetimes: heavy stable charge particles, disappearing tracks, displaced vertices, and missing energy searches. We discuss the applicability of these searches to conversion-driven freeze-out and derive current constraints highlighting their complementarity. For the displaced vertices search, we demonstrate how a slight modification of the current analysis significantly improves its sensitivity to the scenario. △ Less

Submitted 2 September, 2024; v1 submitted 24 April, 2024; originally announced April 2024.

Comments: 12 pages + references, 11 figures. v2: Appendix B added, minor corrections in CMS DT analysis; matches published version

Report number: TTK-23-13

Journal ref: Phys.Rev.D 110 (2024) 1, 015031

Mixed-state quantum anomaly and multipartite entanglement

Authors: Leonardo A. Lessa, Meng Cheng, Chong Wang

Abstract: Quantum entanglement measures of many-body states have been increasingly useful to characterize phases of matter. Here we explore a surprising connection between mixed state entanglement and 't Hooft anomaly. More specifically, we consider lattice systems in $d$ space dimensions with anomalous symmetry $G$ where the anomaly is characterized by an invariant in the group cohomology… ▽ More Quantum entanglement measures of many-body states have been increasingly useful to characterize phases of matter. Here we explore a surprising connection between mixed state entanglement and 't Hooft anomaly. More specifically, we consider lattice systems in $d$ space dimensions with anomalous symmetry $G$ where the anomaly is characterized by an invariant in the group cohomology $H^{d+2}(G,U(1))$. We show that any mixed state $ρ$ that is strongly symmetric under $G$, in the sense that $Gρ\proptoρ$, is necessarily $(d+2)$-nonseparable, i.e. is not the mixture of tensor products of $d+2$ states in the Hilbert space. Furthermore, such states cannot be prepared from any $(d+2)$-separable states using finite-depth local quantum channels, so the nonseparability is long-ranged in nature. We provide proof of these results in $d\leq1$, and plausibility arguments in $d>1$. The anomaly-nonseparability connection thus allows us to generate simple examples of mixed states with nontrivial long-ranged multipartite entanglement. In particular, in $d=1$ we found an example of intrinsically mixed quantum phase, in the sense that states in this phase cannot be two-way connected to any pure state through finite-depth local quantum channels. We also analyze mixed anomaly involving both strong and weak symmetries, including systems constrained by the Lieb-Schultz-Mattis type of anomaly. We find that, while strong-weak mixed anomaly in general does not constrain quantum entanglement, it does constrain long-range correlations of mixed states in nontrivial ways. Namely, such states are not symmetrically invertible and not gapped Markovian, generalizing familiar properties of anomalous pure states. △ Less

Submitted 29 November, 2024; v1 submitted 30 January, 2024; originally announced January 2024.

Comments: 27 pages, 9 figures; New results on strong-weak mixed anomaly and other revisions

Journal ref: Phys. Rev. X 15, 011069 (2025)

Global LHC constraints on electroweak-inos with SModelS v2.3

Authors: Mohammad Mahdi Altakach, Sabine Kraml, Andre Lessa, Sahana Narasimha, Timothée Pascal, Théo Reymermier, Wolfgang Waltenberger

Abstract: Electroweak-inos, superpartners of the electroweak gauge and Higgs bosons, play a special role in supersymmetric theories. Their intricate mixing into chargino and neutralino mass eigenstates leads to a rich phenomenology, which makes it difficult to derive generic limits from LHC data. In this paper, we present a global analysis of LHC constraints for promptly decaying electroweak-inos in the con… ▽ More Electroweak-inos, superpartners of the electroweak gauge and Higgs bosons, play a special role in supersymmetric theories. Their intricate mixing into chargino and neutralino mass eigenstates leads to a rich phenomenology, which makes it difficult to derive generic limits from LHC data. In this paper, we present a global analysis of LHC constraints for promptly decaying electroweak-inos in the context of the minimal supersymmetric standard model, exploiting the SModelS software package. Combining up to 16 ATLAS and CMS searches for which electroweak-ino efficiency maps are available in SModelS, we study which combinations maximise the sensitivity in different regions of the parameter space, how fluctuations in the data in individual analyses influence the global likelihood, and what is the resulting exclusion power of the combination compared to the analysis-by-analysis approach. △ Less

Submitted 8 March, 2024; v1 submitted 27 December, 2023; originally announced December 2023.

Comments: 44 pages, 24 figures, 1 table, minor modifications following referees' suggestions. The input SLHA and SMODELS output files are available on https://zenodo.org/doi/10.5281/zenodo.10471552

Journal ref: SciPost Phys. 16, 101 (2024)

Les Houches guide to reusable ML models in LHC analyses

Authors: Jack Y. Araz, Andy Buckley, Gregor Kasieczka, Jan Kieseler, Sabine Kraml, Anders Kvellestad, Andre Lessa, Tomasz Procter, Are Raklev, Humberto Reyes-Gonzalez, Krzysztof Rolbiecki, Sezen Sekmen, Gokhan Unel

Abstract: With the increasing usage of machine-learning in high-energy physics analyses, the publication of the trained models in a reusable form has become a crucial question for analysis preservation and reuse. The complexity of these models creates practical issues for both reporting them accurately and for ensuring the stability of their behaviours in different environments and over extended timescales.… ▽ More With the increasing usage of machine-learning in high-energy physics analyses, the publication of the trained models in a reusable form has become a crucial question for analysis preservation and reuse. The complexity of these models creates practical issues for both reporting them accurately and for ensuring the stability of their behaviours in different environments and over extended timescales. In this note we discuss the current state of affairs, highlighting specific practical issues and focusing on the most promising technical and strategic approaches to ensure trustworthy analysis-preservation. This material originated from discussions in the LHC Reinterpretation Forum and the 2023 PhysTeV workshop at Les Houches. △ Less

Submitted 11 September, 2024; v1 submitted 22 December, 2023; originally announced December 2023.

Comments: 12 pages; v2: added funding acknowledgement; v3 update in response to referee comments

Journal ref: SciPost Phys. Comm. Rep. 3 (2024)

Braneworlds in Warped Einsteinian Cubic Gravity

Authors: L. A. Lessa, R. V. Maluf, J. E. G. Silva, C. A. S. Almeida

Abstract: Einstenian cubic gravity (ECG) is a modified theory of gravity constructed with cubic contractions of the curvature tensor. This theory has the remarkable feature of having the same two propagating degrees of freedom of Einstein gravity (EG), at the perturbative level on maximally symmetric spacetimes. The additional unstable modes steaming from the higher order derivative dynamics are suppressed… ▽ More Einstenian cubic gravity (ECG) is a modified theory of gravity constructed with cubic contractions of the curvature tensor. This theory has the remarkable feature of having the same two propagating degrees of freedom of Einstein gravity (EG), at the perturbative level on maximally symmetric spacetimes. The additional unstable modes steaming from the higher order derivative dynamics are suppressed provided that we consider the ECG as an effective field theory wherein the cubic terms are seen as perturbative corrections of the Einstein-Hilbert term. Extensions of ECG have been proposed in cosmology and compact objects in order to probe if this property holds in more general configurations. In this work, we construct a modified ECG gravity in a five dimensional warped braneworld scenario. By assuming a specific combination of the cubic parameters, we obtained modified gravity equations of motion with terms up to second-order. For a thin 3-brane, the cubic-gravity corrections yield an effective positive bulk cosmological constant. Thus, in order to keep the 5D bulk warped compact, an upper bound of the cubic parameter with respect to the bulk curvature was imposed. For a thick brane, the cubic-gravity terms modify the scalar field potential and its corresponding vacuum. Nonetheless, the domain-wall structure with a localized source is preserved. At the perturbative level, the Kaluza-Klein (KK) tensor gravitational modes are stable and possess a localized massless mode provided the cubic corrections are small compared to the EG braneworld. △ Less

Submitted 30 May, 2024; v1 submitted 11 December, 2023; originally announced December 2023.

Journal ref: JCAP 05 (2024) 123

Going beyond Top EFT

Authors: André Lessa, Verónica Sanz

Abstract: We present a new way to interpret Top Standard Model measurements going beyond the SMEFT framework. Instead of the usual paradigm in Top EFT, where the main effects come from tails in momenta distributions, we propose an interpretation in terms of new physics which only shows up at loop-level. The effects of these new states, which can be lighter than required within the SMEFT, appear as distincti… ▽ More We present a new way to interpret Top Standard Model measurements going beyond the SMEFT framework. Instead of the usual paradigm in Top EFT, where the main effects come from tails in momenta distributions, we propose an interpretation in terms of new physics which only shows up at loop-level. The effects of these new states, which can be lighter than required within the SMEFT, appear as distinctive structures at high momenta, but may be suppressed at the tails of distributions. As an illustration of this phenomena, we present the explicit case of a UV model with a $\mathcal{Z}_2$ symmetry, including a Dark Matter candidate and a top-partner. This simple UV model reproduces the main features of this class of signatures, particularly a momentum-dependent form factor with more structure than the SMEFT. As the new states can be lighter than in SMEFT, we explore the interplay between the reinterpretation of direct searches for colored states and Dark Matter, and Top measurements made by ATLAS and CMS in the differential $t \bar t$ final state. We also compare our method with what one would expect using the SMEFT reinterpretation, finding that using the full loop information provides a better discriminating power. △ Less

Submitted 24 April, 2024; v1 submitted 1 December, 2023; originally announced December 2023.

Comments: 27 pages, 12 figures. The datasets used to obtain all the results presented here as well as additional details are available in https://zenodo.org/records/10277973

Journal ref: JHEP 04 107 (2024)

Einstein-Bumblebee-Dilaton black hole in Lifshitz spacetimes

Authors: L. A. Lessa, J. E. G. Silva

Abstract: We investigate the critical behavior of Lifshitz black holes in Einstein-dilaton gravity in the context of spontaneous Lorentz symmetry breaking. Considering the effects of both the bumblebee vacuum expectation value (VEV) and the fluctuations over the VEV, we obtained new asymptotically Lifshitz charged solutions in (3 + 1) dimensions. We consider the longitudinal massive mode of Lorentz Violatio… ▽ More We investigate the critical behavior of Lifshitz black holes in Einstein-dilaton gravity in the context of spontaneous Lorentz symmetry breaking. Considering the effects of both the bumblebee vacuum expectation value (VEV) and the fluctuations over the VEV, we obtained new asymptotically Lifshitz charged solutions in (3 + 1) dimensions. We consider the longitudinal massive mode of Lorentz Violation (LV) as thermodynamic pressure, leading us to establish an P-V extended phase space. Within this framework, we derive the equation of state P(T,V), and subsequently identify the critical points, which manifest as discontinuities in the specific heat at constant pressure. Following this, we compute the Gibbs free energy, revealing a first-order phase transition within the model. Finally, we determine the critical exponents, demonstrating their equivalence to those observed in the Van der Waals system. △ Less

Submitted 13 September, 2023; originally announced September 2023.

Einstein-Bumblebee-Dilaton black hole solution

Authors: L. A. Lessa, J. E. G. Silva

Abstract: We obtain new black hole solutions in a Einstein-Bumblebee-scalar theory. By starting with a Einstein-Bumblebee theory in D + d dimensions, the scalar dilaton field and its interaction with the gravitational and bumblebee fields are obtained by Kaluza-Klein (KK) reduction over the extra dimensions. Considering the effects of both the bumblebee vacuum expectation value (VEV) and the fluctuations ov… ▽ More We obtain new black hole solutions in a Einstein-Bumblebee-scalar theory. By starting with a Einstein-Bumblebee theory in D + d dimensions, the scalar dilaton field and its interaction with the gravitational and bumblebee fields are obtained by Kaluza-Klein (KK) reduction over the extra dimensions. Considering the effects of both the bumblebee vacuum expectation value (VEV) and the fluctuations over the VEV, we obtained new charged solutions in (3 + 1) dimensions. For a vanishing dilaton, the black hole turned out to be a charged de Sitter-Reissner-Nordstrom solution, where the transverse mode is the Maxwell field and the longitudinal mode is the cosmological constant. The stability of these new solutions is investigated by means of the analysis of the black hole thermodynamics. The temperature, entropy and heat capacity show that these modified black holes are thermodynamic stable. △ Less

Submitted 17 November, 2023; v1 submitted 28 August, 2023; originally announced August 2023.

Comments: 19 pages, 4 figures

Journal ref: Eur. Phys. J. C 83, 1035 (2023)

SModelS v2.3: enabling global likelihood analyses

Authors: Mohammad Mahdi Altakach, Sabine Kraml, Andre Lessa, Sahana Narasimha, Timothée Pascal, Wolfgang Waltenberger

Abstract: We present version 2.3 of SModelS, a public tool for the fast reinterpretation of LHC searches for new physics on the basis of simplified-model results. The main new features are a database update with the latest available experimental results for full Run 2 luminosity, comprising in particular a large variety of electroweak-ino searches, and the ability to combine likelihoods from different analy… ▽ More We present version 2.3 of SModelS, a public tool for the fast reinterpretation of LHC searches for new physics on the basis of simplified-model results. The main new features are a database update with the latest available experimental results for full Run 2 luminosity, comprising in particular a large variety of electroweak-ino searches, and the ability to combine likelihoods from different analyses. This enables statistically more rigorous constraints and opens the way for global likelihood analyses for LHC searches. The physics impact is demonstrated for the electroweak-ino sector of the minimal supersymmetric standard model. △ Less

Submitted 21 August, 2023; v1 submitted 30 June, 2023; originally announced June 2023.

Comments: 34 pages, 13 figures, 3 tables. The program and an extensive online documentation are available at https://smodels.github.io/. The dataset used in section 4 is available at https://doi.org/10.5281/zenodo.8086949

Journal ref: SciPost Phys. 15, 185 (2023)

Regular black holes in Einstein cubic gravity

Authors: L. A. Lessa, J. E. G. Silva

Abstract: We investigate the effects of the Einstein cubic gravity (ECG) on regular black hole solutions driven by nonlinear electrodynamics (NLE) sources. The ECG tends to form a naked singularity at the origin for a high ECG coupling constant. Assuming that ECG provides only perturbative corrections to the regular magnetic charged solutions, we found modified regular solutions with a de Sitter-like core w… ▽ More We investigate the effects of the Einstein cubic gravity (ECG) on regular black hole solutions driven by nonlinear electrodynamics (NLE) sources. The ECG tends to form a naked singularity at the origin for a high ECG coupling constant. Assuming that ECG provides only perturbative corrections to the regular magnetic charged solutions, we found modified regular solutions with a de Sitter-like core whose cosmological constant depends on the magnetic charge and the ECG coupling constant. The thermodynamic stability is investigated by means of the Hawking temperature and the heat capacity. In fact, for a small charge and ECG coupling, the Hawking temperature is regularized, leaving a thermodynamic stable remnant for a small $r_h \neq 0$. The heat capacity reveals that the ECG regular black hole undergoes a phase transition between an unstable into a stable configuration. △ Less

Submitted 29 May, 2023; originally announced May 2023.

Comments: 23 pages, 5 figures

Measurement as a shortcut to long-range entangled quantum matter

Authors: Tsung-Cheng Lu, Leonardo A. Lessa, Isaac H. Kim, Timothy H. Hsieh

Abstract: The preparation of long-range entangled states using unitary circuits is limited by Lieb-Robinson bounds, but circuits with projective measurements and feedback (``adaptive circuits'') can evade such restrictions. We introduce three classes of local adaptive circuits that enable low-depth preparation of long-range entangled quantum matter characterized by gapped topological orders and conformal fi… ▽ More The preparation of long-range entangled states using unitary circuits is limited by Lieb-Robinson bounds, but circuits with projective measurements and feedback (``adaptive circuits'') can evade such restrictions. We introduce three classes of local adaptive circuits that enable low-depth preparation of long-range entangled quantum matter characterized by gapped topological orders and conformal field theories (CFTs). The three classes are inspired by distinct physical insights, including tensor-network constructions, multiscale entanglement renormalization ansatz (MERA), and parton constructions. A large class of topological orders, including chiral topological order, can be prepared in constant depth or time, and one-dimensional CFT states and non-abelian topological orders with both solvable and non-solvable groups can be prepared in depth scaling logarithmically with system size. We also build on a recently discovered correspondence between symmetry-protected topological phases and long-range entanglement to derive efficient protocols for preparing symmetry-enriched topological order and arbitrary CSS (Calderbank-Shor-Steane) codes. Our work illustrates the practical and conceptual versatility of measurement for state preparation. △ Less

Submitted 12 April, 2023; v1 submitted 27 June, 2022; originally announced June 2022.

Comments: 23 pages, 9 figures; updated to the published version

Journal ref: PRX Quantum 3, 040337 (2022)

Data and Analysis Preservation, Recasting, and Reinterpretation

Authors: Stephen Bailey, Christian Bierlich, Andy Buckley, Jon Butterworth, Kyle Cranmer, Matthew Feickert, Lukas Heinrich, Axel Huebl, Sabine Kraml, Anders Kvellestad, Clemens Lange, Andre Lessa, Kati Lassila-Perini, Christine Nattrass, Mark S. Neubauer, Sezen Sekmen, Giordon Stark, Graeme Watt

Abstract: We make the case for the systematic, reliable preservation of event-wise data, derived data products, and executable analysis code. This preservation enables the analyses' long-term future reuse, in order to maximise the scientific impact of publicly funded particle-physics experiments. We cover the needs of both the experimental and theoretical particle physics communities, and outline the goals… ▽ More We make the case for the systematic, reliable preservation of event-wise data, derived data products, and executable analysis code. This preservation enables the analyses' long-term future reuse, in order to maximise the scientific impact of publicly funded particle-physics experiments. We cover the needs of both the experimental and theoretical particle physics communities, and outline the goals and benefits that are uniquely enabled by analysis recasting and reinterpretation. We also discuss technical challenges and infrastructure needs, as well as sociological challenges and changes, and give summary recommendations to the particle-physics community. △ Less

Submitted 18 March, 2022; originally announced March 2022.

Comments: 25 pages, 4 sets of recommendations. Contribution to Snowmass 2021

Constraining new physics with SModelS version 2

Authors: Gaël Alguero, Jan Heisig, Charanjit Khosa, Sabine Kraml, Suchita Kulkarni, Andre Lessa, Humberto Reyes-González, Wolfgang Waltenberger, Alicia Wongel

Abstract: We present version 2 of SModelS, a program package for the fast reinterpretation of LHC searches for new physics on the basis of simplified model results. The major novelty of the SModelS v2 series is an extended topology description with a flexible number of particle attributes, such as spin, charge, decay width, etc. This enables, in particular, the treatment of a wide range of signatures with l… ▽ More We present version 2 of SModelS, a program package for the fast reinterpretation of LHC searches for new physics on the basis of simplified model results. The major novelty of the SModelS v2 series is an extended topology description with a flexible number of particle attributes, such as spin, charge, decay width, etc. This enables, in particular, the treatment of a wide range of signatures with long-lived particles. Moreover, constraints from prompt and long-lived searches can be evaluated simultaneously in the same run. The current database includes results from searches for heavy stable charged particles, disappearing tracks, displaced jets and displaced leptons, in addition to a large number of prompt searches. The capabilities of the program are demonstrated by two physics applications: constraints on long-lived charged scalars in the scotogenic model, and constraints on the electroweak-ino sector in the Minimal Supersymmetric Standard Model. △ Less

Submitted 1 December, 2021; originally announced December 2021.

Comments: 42 pages, 15 figures, 3 tables. The program and an extensive online documentation are available at https://smodels.github.io/

Report number: TTK-21-50

Leptoquark manoeuvres in the dark: a simultaneous solution of the dark matter problem and the $R_{D^{(*)}}$ anomalies

Authors: Geneviève Belanger, Aoife Bharucha, Benjamin Fuks, Andreas Goudelis, Jan Heisig, Adil Jueid, Andre Lessa, Kirtimaan A. Mohan, Giacomo Polesello, Priscilla Pani, Alexander Pukhov, Dipan Sengupta, José Zurita

Abstract: The measured branching fractions of $B$-mesons into leptonic final states derived by the LHCb collaboration hint towards the breakdown of lepton flavour universality. In this work we take at face value the so-called $R_{D^{(*)}}$ observables that are defined as the ratios of neutral $B$-meson charged-current decays into a charged $D$-meson, a charged lepton and a neutrino final state in the tau an… ▽ More The measured branching fractions of $B$-mesons into leptonic final states derived by the LHCb collaboration hint towards the breakdown of lepton flavour universality. In this work we take at face value the so-called $R_{D^{(*)}}$ observables that are defined as the ratios of neutral $B$-meson charged-current decays into a charged $D$-meson, a charged lepton and a neutrino final state in the tau and muon channels. A well-studied and simple solution to this charged current anomaly is to introduce a scalar leptoquark $S_1$ that couples to the second and third generation of fermions. We investigate how $S_1$ can also serve as a mediator between the Standard Model and a dark sector. We study this scenario in detail and estimate the constraints arising from collider searches for leptoquarks, collider searches for missing energy signals, direct detection experiments and the dark matter relic abundance. We stress that the production of a pair of leptoquarks that decays into different final states (i.e. the commonly called "mixed" channels) provides critical information for identifying the underlying dynamics, and we exemplify this by studying the $t τb ν$ and the resonant $S_1$ plus missing energy channels. We find that direct detection data provides non-negligible constraints on the leptoquark coupling to the dark sector, which in turn affects the relic abundance. We also show that the correct relic abundance can not only arise via standard freeze-out, but also through conversion-driven freeze-out. We illustrate the rich phenomenology of the model with a few selected benchmark points, providing a broad stroke of the interesting connection between lepton flavour violation and dark matter. △ Less

Submitted 10 February, 2022; v1 submitted 15 November, 2021; originally announced November 2021.

Comments: v2: 60 pages, minor changes, added references. Matches the published version

Report number: KIAS-Q21013, MSUHEP-21-031, IFIC/21-46, TTK-21-44, P3H-21-091

The bumblebee field excitations in a cosmological braneworld

Authors: L. A. Lessa, J. E. G. Silva, C. A. S. Almeida

Abstract: We investigated the effects of the spacetime curvature and extra dimensions on the excitations of a self-interacting vector field known as the bumblebee field. The self-interacting quadratic potential breaks the gauge invariance and the vacuum expectation value (VEV) of the bumblebee field $b_M$ violates the local particle Lorentz symmetry. By assuming the bumblebee field living in a $AdS_{5}$ bul… ▽ More We investigated the effects of the spacetime curvature and extra dimensions on the excitations of a self-interacting vector field known as the bumblebee field. The self-interacting quadratic potential breaks the gauge invariance and the vacuum expectation value (VEV) of the bumblebee field $b_M$ violates the local particle Lorentz symmetry. By assuming the bumblebee field living in a $AdS_{5}$ bulk, we found an exponential suppression of the self-interacting constant $λ$ and the bumblebee VEV along the extra dimension. The fluctuations of the bumblebee upon the VEV can be decomposed into transverse and longitudinal modes with respect to $b_{M}$. Despite the curvature, the transverse mode acquires massive Kaluza-Klein towers, while the longitudinal mode acquires LV mass $λb^{2}$. On the other hand, the current conservation law prevents massive Kaluza-Klein modes for the longitudinal mode. For a spacelike $b_{M}$ along the extra dimension and assuming a FRW 3-brane embedded in the $AdS_{5}$ yields to an additional dissipative term to the longitudinal mode. The cosmological expansion leads to decay of the longitudinal mode in a time $Δt \approx H^{-1}$, where $H=\dot{a}/a$ is the Hubble parameter and $a(t)$ is the scale factor. For a timelike $b_{M}$, the longitudinal mode does not propagate on the brane and its amplitude decays in time with $a^{-3}$ and in the extra dimension with $z^{-λb^{2}l^{2}}$. △ Less

Submitted 17 December, 2021; v1 submitted 2 August, 2021; originally announced August 2021.

Comments: 15 pages, no figure

Artificial proto-modelling with simplified-model results from the LHC

Authors: Sabine Kraml, Andre Lessa, Wolfgang Waltenberger

Abstract: We present a novel approach to identify potential dispersed signals of new physics in the slew of published LHC results. It employs a random walk algorithm to introduce sets of new particles, dubbed "proto-models", which are tested against simplified-model results from ATLAS and CMS searches for new physics by exploiting the SModelS software framework. A combinatorial algorithm identifies the set… ▽ More We present a novel approach to identify potential dispersed signals of new physics in the slew of published LHC results. It employs a random walk algorithm to introduce sets of new particles, dubbed "proto-models", which are tested against simplified-model results from ATLAS and CMS searches for new physics by exploiting the SModelS software framework. A combinatorial algorithm identifies the set of analyses and/or signal regions that maximally violates the Standard Model hypothesis, while remaining compatible with the entirety of LHC constraints in our database. Crucial to the method is the ability to construct a reliable likelihood in proto-model space; we explain the various approximations which are needed depending on the information available from the experiments, and how they impact the whole procedure. △ Less

Submitted 19 May, 2021; originally announced May 2021.

Comments: 6 pages; contribution to the 2021 QCD session of the 55th Rencontres de Moriond

Artificial Proto-Modelling: Building Precursors of a Next Standard Model from Simplified Model Results

Authors: Wolfgang Waltenberger, André Lessa, Sabine Kraml

Abstract: We present a novel algorithm to identify potential dispersed signals of new physics in the slew of published LHC results. It employs a random walk algorithm to introduce sets of new particles, dubbed "proto-models", which are tested against simplified-model results from ATLAS and CMS (exploiting the SModelS software framework). A combinatorial algorithm identifies the set of analyses and/or signal… ▽ More We present a novel algorithm to identify potential dispersed signals of new physics in the slew of published LHC results. It employs a random walk algorithm to introduce sets of new particles, dubbed "proto-models", which are tested against simplified-model results from ATLAS and CMS (exploiting the SModelS software framework). A combinatorial algorithm identifies the set of analyses and/or signal regions that maximally violates the SM hypothesis, while remaining compatible with the entirety of LHC constraints in our database. Demonstrating our method by running over the experimental results in the SModelS database, we find as currently best-performing proto-model a top partner, a light-flavor quark partner, and a lightest neutral new particle with masses of the order of 1.2 TeV, 700 GeV and 160 GeV, respectively. The corresponding global p-value for the SM hypothesis is approximately 0.19; by construction no look-elsewhere effect applies. △ Less

Submitted 15 March, 2021; v1 submitted 22 December, 2020; originally announced December 2020.

Comments: 54 pages, 14 figures, two references added in v2. v3 accepted for publication in JHEP. Homepage: https://smodels.github.io/protomodels

Journal ref: Journal of High Energy Physics 2021, 207 (2021)

New developments in SModelS

Authors: Gaël Alguero, Jan Heisig, Charanjit K. Khosa, Sabine Kraml, Suchita Kulkarni, Andre Lessa, Philipp Neuhuber, Humberto Reyes-González, Wolfgang Waltenberger, Alicia Wongel

Abstract: SModelS is an automatized tool enabling the fast interpretation of simplified model results from the LHC within any model of new physics respecting a $\mathbb{Z}_2$ symmetry. In this contribution, we report on two important updates of SModelS during 2020: the extension of the SModelS' database with 13 ATLAS and 10 CMS analyses, including 5 ATLAS and 1 CMS analyses at full Run~2 luminosity, and the… ▽ More SModelS is an automatized tool enabling the fast interpretation of simplified model results from the LHC within any model of new physics respecting a $\mathbb{Z}_2$ symmetry. In this contribution, we report on two important updates of SModelS during 2020: the extension of the SModelS' database with 13 ATLAS and 10 CMS analyses, including 5 ATLAS and 1 CMS analyses at full Run~2 luminosity, and the ability to use full likelihoods now provided by ATLAS in the form of pyhf JSON files. Moreover, we briefly explain how to use SModelS and give an overview of ongoing developments. △ Less

Submitted 15 December, 2020; originally announced December 2020.

Comments: 16 pages, 7 figures, Contribution to "Tools for High Energy Physics and Cosmology" (TOOLS2020), 2-6 Nov. 2020, IP2I Lyon, France

Traversable wormhole solution with a background Kalb-Ramond field

Authors: L. A. Lessa, R. Oliveira, J. E. G. Silva, C. A. S. Almeida

Abstract: We obtain a static spherically symmetric wormhole solution due to the vacuum expectation value (VEV) of a Kalb-Ramond field. The Kalb-Ramond VEV is a background tensor field which produces a local Lorentz symmetry breaking (LSB) of spacetime. Considering a non-minimal coupling between the Kalb-Ramond (VEV) and the Ricci tensor, we found an exact traversable wormhole solution sustained by matter so… ▽ More We obtain a static spherically symmetric wormhole solution due to the vacuum expectation value (VEV) of a Kalb-Ramond field. The Kalb-Ramond VEV is a background tensor field which produces a local Lorentz symmetry breaking (LSB) of spacetime. Considering a non-minimal coupling between the Kalb-Ramond (VEV) and the Ricci tensor, we found an exact traversable wormhole solution sustained by matter sources with a negative isotropic pressure. The matter source satisfies the energy conditions at the throat for particular choices of the LSB parameter. Moreover, we employ the Gauss-Bonnet method to analyze the deflection angle of light in the weak limit approximation. △ Less

Submitted 11 October, 2020; originally announced October 2020.

Comments: 16 pages, 2 figures

SModelS database update v1.2.3

Authors: Charanjit K. Khosa, Sabine Kraml, Andre Lessa, Philipp Neuhuber, Wolfgang Waltenberger

Abstract: We present an update of the SModelS database with simplified model results from 13 ATLAS and 10 CMS searches for supersymmetry at Run 2. This includes 5 ATLAS and 1 CMS analyses for full Run 2 luminosity, i.e. close to 140/fb of data. In total, 76 official upper limit and efficiency map results have been added. Moreover, 21 efficiency map results have been produced by us using MadAnalysis5, to imp… ▽ More We present an update of the SModelS database with simplified model results from 13 ATLAS and 10 CMS searches for supersymmetry at Run 2. This includes 5 ATLAS and 1 CMS analyses for full Run 2 luminosity, i.e. close to 140/fb of data. In total, 76 official upper limit and efficiency map results have been added. Moreover, 21 efficiency map results have been produced by us using MadAnalysis5, to improve the coverage of gluino-squark production. The constraining power of the new database, v1.2.3, is compared to that of the previous release, v1.2.2. SModelS v1.2.3 is publicly available and can readily be employed for physics studies. △ Less

Submitted 1 September, 2020; v1 submitted 1 May, 2020; originally announced May 2020.

Comments: 7 pages, 2 figures, 4 tables. Published version. The program is available at https://smodels.github.io/

Journal ref: LHEP-158, 2020

Reinterpretation of LHC Results for New Physics: Status and Recommendations after Run 2

Authors: Waleed Abdallah, Shehu AbdusSalam, Azar Ahmadov, Amine Ahriche, Gaël Alguero, Benjamin C. Allanach, Jack Y. Araz, Alexandre Arbey, Chiara Arina, Peter Athron, Emanuele Bagnaschi, Yang Bai, Michael J. Baker, Csaba Balazs, Daniele Barducci, Philip Bechtle, Aoife Bharucha, Andy Buckley, Jonathan Butterworth, Haiying Cai, Claudio Campagnari, Cari Cesarotti, Marcin Chrzaszcz, Andrea Coccaro, Eric Conte , et al. (117 additional authors not shown)

Abstract: We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentati… ▽ More We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentation of LHC results in order to better enable reinterpretation in the future. We also provide a brief description of existing software reinterpretation frameworks and recent global analyses of new physics that make use of the current data. △ Less

Submitted 21 July, 2020; v1 submitted 17 March, 2020; originally announced March 2020.

Comments: 58 pages, minor revision following comments from SciPost referees

Report number: CERN-LPCC-2020-001, FERMILAB-FN-1098-CMS-T, Imperial/HEP/2020/RIF/01

Journal ref: SciPost Phys. 9, 022 (2020)

Les Houches 2019 Physics at TeV Colliders: New Physics Working Group Report

Authors: G. Brooijmans, A. Buckley, S. Caron, A. Falkowski, B. Fuks, A. Gilbert, W. J. Murray, M. Nardecchia, J. M. No, R. Torre, T. You, G. Zevi Della Porta, G. Alguero, J. Y. Araz, S. Banerjee, G. Bélanger, T. Berger-Hryn'ova, J. Bernigaud, A. Bharucha, D. Buttazzo, J. M. Butterworth, G. Cacciapaglia, A. Coccaro, L. Corpe, N. Desai , et al. (65 additional authors not shown)

Abstract: This report presents the activities of the `New Physics' working group for the `Physics at TeV Colliders' workshop (Les Houches, France, 10--28 June, 2019). These activities include studies of direct searches for new physics, approaches to exploit published data to constrain new physics, as well as the development of tools to further facilitate these investigations. Benefits of machine learning fo… ▽ More This report presents the activities of the `New Physics' working group for the `Physics at TeV Colliders' workshop (Les Houches, France, 10--28 June, 2019). These activities include studies of direct searches for new physics, approaches to exploit published data to constrain new physics, as well as the development of tools to further facilitate these investigations. Benefits of machine learning for both the search for new physics and the interpretation of these searches are also presented. △ Less

Submitted 27 February, 2020; originally announced February 2020.

Comments: Proceedings of the BSM Session of the Les Houches 2019 workshop, 227 pages

Brazilian Community Report on Dark Matter

Authors: E. Abdalla, I. F. M. Albuquerque, A. Alves, L. Barosi, M. C. Q. Bazetto, R. C. Batista, C. A. Bernardes, C. Bonifazi, H. A. Borges, F. A. Brito, T. R. P. Caramês, L. Casarini, D. Cogollo, A. G. Dias, A. Esmaili, M. M. Ferreira, G. Gil da Silveira, M. M. Guzzo, D. Hadjimichef, P. C. de Holanda, E. Kemp, A. Lessa, G. Lichtenstein, A. A. Machado, M. Makler , et al. (30 additional authors not shown)

Abstract: This white paper summarizes the activities of the Brazilian community concerning dark matter physics and highlights the importance of financial support to Brazilian groups that are deeply involved in experimental endeavours. The flagships of the Brazilian dark matter program are the Cherenkov Telescope Array, DARKSIDE, SBN and LHC experiments, but we emphasize that smaller experiments such as DAMI… ▽ More This white paper summarizes the activities of the Brazilian community concerning dark matter physics and highlights the importance of financial support to Brazilian groups that are deeply involved in experimental endeavours. The flagships of the Brazilian dark matter program are the Cherenkov Telescope Array, DARKSIDE, SBN and LHC experiments, but we emphasize that smaller experiments such as DAMIC and CONNIE constitute important probes to dark sectors as well and should receive special attention. Small experimental projects showing the potential to probe new regions of parameter space of dark matter models are encouraged. On the theoretical and phenomenological side, some groups are devoted to astrophysical aspects such as the dark matter density profile while others explore the signature of dark matter models at colliders, direct and indirect detection experiments. In summary, the Brazilian dark matter community that was born not long ago has grown tremendously in the past years and now plays an important role in the hunt for a dark matter particle. △ Less

Submitted 20 December, 2019; originally announced December 2019.

Comments: 10 pages, 1 figure

Modified black hole solution with a background Kalb-Ramond field

Authors: L. A. Lessa, J. E. G. Silva, R. V. Maluf, C. A. S. Almeida

Abstract: We study the gravitation effects on a static and spherically symmetric spacetime due to the vacuum expectation value (VEV) of a Kalb-Ramond field. The Kalb-Ramond VEV is a background tensor field which produces a local Lorentz symmetry breaking (LSB) of spacetime. Considering a non-minimal coupling between the Kalb-Ramond (VEV) and the Ricci tensor, we obtain an exact parameter-dependent power-law… ▽ More We study the gravitation effects on a static and spherically symmetric spacetime due to the vacuum expectation value (VEV) of a Kalb-Ramond field. The Kalb-Ramond VEV is a background tensor field which produces a local Lorentz symmetry breaking (LSB) of spacetime. Considering a non-minimal coupling between the Kalb-Ramond (VEV) and the Ricci tensor, we obtain an exact parameter-dependent power-law modified black hole. For a particular choice of the LSB parameter, the Lorentz violation produces a solution similar to the Reissner-Nordstrom, despite the absence of charge. The near-horizon geometry is modified by including a new inner horizon and shifting the Schwarzschild horizon. Asymptotically, the usual Minkowski spacetime with a background tensor field is recovered. The vacuum configurations are studied considering the energy conditions and the Lorentz violating source properties. By means of the mercury perihelion test, an upper bound to the local Lorentz violation (LV) is obtained, and its corresponding effects on the black hole temperature is investigated. △ Less

Submitted 29 May, 2020; v1 submitted 22 November, 2019; originally announced November 2019.

Comments: 9 pages. Published version

Journal ref: Eur. Phys. J. C 80, 335 (2020)

Confronting minimal freeze-in models with the LHC

Authors: G. Bélanger, N. Desai, A. Goudelis, J. Harz, A. Lessa, J. M. No, A. Pukhov, S. Sekmen, D. Sengupta, B. Zaldivar, J. Zurita

Abstract: We present a class of dark matter models, in which the dark matter particle is a feebly interacting massive particle (FIMP) produced via the decay of an electrically charged and/or colored parent particle. Given the feeble interaction, dark matter is produced via the freeze-in mechanism and the parent particle is long-lived. The latter leads to interesting collider signatures. We study current LHC… ▽ More We present a class of dark matter models, in which the dark matter particle is a feebly interacting massive particle (FIMP) produced via the decay of an electrically charged and/or colored parent particle. Given the feeble interaction, dark matter is produced via the freeze-in mechanism and the parent particle is long-lived. The latter leads to interesting collider signatures. We study current LHC constrains on our models arising from searches for heavy charged particles, disappearing tracks, displaced leptons and displaced vertices. We demonstrate not only that collider searches can be a powerful probe of the freeze-in dark matter models under consideration, but that an observation can lead as well to interesting insights on the reheating temperature and thus on the validity of certain baryogenesis models. △ Less

Submitted 30 September, 2019; originally announced October 2019.

Comments: 6 pages, 3 figures. Contribution to the proceedings of Rencontres de Moriond EW 2019, 16-23 March 2019, La Thuile, Italy

Report number: TUM-HEP-1204-19