Article
Physics, Particles & Fields
Polina Petriakova, Arkady A. Popov, Sergey G. Rubin
Summary: This paper discusses the origin of small parameters and aims to explain the Hierarchy problem. Flexible extra dimensions play a crucial role in the formation of physical parameters. The evolution of multidimensional metric starts from the Planck scale and ends with a static extra-dimensional metric and a 4-dimensional de Sitter space at high energies, leading to exponentially produced causally disconnected universes. Quantum fluctuations independently distort the metric within these universes, causing inflationary processes. Some universes asymptotically tend towards states characterized by small Hubble parameters. The explanation for the effective parameter reduction in the Higgs sector of the Standard Model lies in the presence of small-amplitude distributions of a scalar field in a fraction of these universes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
R. Jalalzadeh, S. Jalalzadeh, B. Malekolkalami
Summary: We investigate an isometrically embedded Bianchi type-V cosmology braneworld model in a D-dimensional bulk space. The model provides a fluid of geometric dark energy (GDE) and unification of fundamental forces similar to the Kaluza-Klein (KK) theory. Factors such as the Planck energy density, the fine structure constant, the muon mass, and the number of extra dimensions determine the density of the induced GDE. Our model predicts that the graviton has mass determined by the induced cosmological constant (CC). Our results suggest that if the Universe has 22 non-compact extra dimensions, they are compatible with observations of the standard model of cosmology. This model offers an alternative method for probing extra dimensions.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Physics, Particles & Fields
A. de Giorgi, S. Vogl
Summary: This study investigates dark matter interactions with a massive spin-2 mediator in a warped extra-dimensional model. It is found that including the full KK-tower leads to unphysical growth in the annihilation process, which cancels out when considering the full field content of the extra-dimensional theory. This challenges the universal applicability of previous studies with spin-2 mediators and prompts a reevaluation of the parameter space for gravitationally interacting scalar dark matter in warped extra-dimensions.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Dmitry Chirkov, Alex Giacomini, Sergey A. Pavluchenko, Alexey Toporensky
Summary: The paper systematically investigates solutions with static compact extra dimensions and expanding three-dimensional subspace, providing a scheme for constructing solutions with stability analysis. It finds that solutions with negative spatial curvature of extra dimensions are always stable, while those with positive curvature are stable for a narrow range of parameters. Differences between positive and negative curvature cases, including the coexistence with maximally-symmetric solutions, are noted and discussed.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Particles & Fields
Nicolas Bernal, Andrea Donini, Miguel G. Folgado, Nuria Rius
Summary: This study explores the possibility of Dark Matter being made of Feebly Interacting Massive Particles interacting gravitationally with Standard Model particles in the Clockwork/Linear Dilaton (CW/LD) model. The study concludes that a significant region of parameter space in the CW/LD model can reproduce the observed Dark Matter relic abundance with scalar DM mass in the MeV range, similar to the results in the Randall-Sundrum (RS) scenario.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Akash K. Mishra, Abhirup Ghosh, Sumanta Chakraborty
Summary: The presence of extra dimensions affects the spacetime geometry of rotating black holes, and the additional parameter beta modifies the quasi-normal modes. By numerically solving the gravitational field equations and analyzing data, the range of beta values is constrained, leading to implications and future directions.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Ujjal Kumar Dey, Utpal Sarkar
Summary: A new scenario is proposed in this study to explain the dark energy problem through the formation of neutrino condensates. By breaking lepton number symmetry on a distant brane, the smallness of neutrino masses and the scale of dark energy are protected, with all lepton number violating effects suppressed in the extra dimensions. Additionally, a lepton number violating soft-term induced from the distant brane results in a light pseudo-Nambu-Goldstone boson acting as the mediator of the attractive force forming the condensates.
Article
Astronomy & Astrophysics
Graciela B. Gelmini, Alexander Kusenko, Volodymyr Takhistov
Summary: Observations in the local Universe have found a discrepancy in the value of the Hubble constant H-0 compared to early Universe measurements, which can potentially be alleviated by the additional radiation from an unstable sterile neutrino with a mass of O(10) MeV before the Big Bang Nucleosynthesis. The necessary masses and couplings of the sterile neutrino, assumed to primarily mix with ν(τ) and/or ν(μ) neutrinos, are within reach of experiments like Super-Kamiokande, NA62, and DUNE.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Mattia Atzori Corona, Riccardo Murgia, Matteo Cadeddu, Maria Archidiacono, Stefano Gariazzo, Carlo Giunti, Steen Hannestad
Summary: This study reassesses a cosmological model with an additional sterile neutrino species and investigates its viability using various cosmic microwave background data. The model is found to resolve the Hubble tension but is constrained by high-multipole polarization data. Interestingly, when using ACT data, there is a possibility of a non-zero sterile neutrino mass, consistent with anomalies observed in short-baseline neutrino oscillation experiments. However, the combined analysis with Planck still favors the ACDM model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Stephon Alexander, Heliudson Bernardo, Michael W. Toomey
Summary: We propose a kinetically mixed dark sector model to resolve the tensions in the Hubble and S8 parameters. Our model, inspired by string theory, includes an axion and a dilaton. Unlike other axio-dilaton models, our theory incorporates kinetic mixing between the two fields, allowing efficient energy transfer and avoiding the need for fine-tuned potentials. This model also has implications for the growth of perturbations and the potential connection to dark energy.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Soumya Jana, Charles Dalang, Lucas Lombriser
Summary: The article investigates a method of transforming higher-dimensional actions into effective four-dimensional scalar-tensor theories, and finds a subset of Horndeski theories through the higher-dimensional Ricci scalar and a subclass of metric ansatz.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
Peter Adshead, Pranjal Ralegankar, Jessie Shelton
Summary: This study updates constraints on dark radiation in millicharged particle and gauged baryon-number-minus-lepton-number extensions of the Standard Model, while also proposing approximations, analyzing quantum-statistical and out-of-equilibrium effects, and considering the finite lifetime of the B - L gauge boson.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
S. Girmohanta, R. N. Mohapatra, R. Shrock
Summary: The study uses a low-energy effective field theory approach to investigate the properties of models with large extra dimensions where quarks and leptons have localized wave functions. It focuses on the lepton sector of models with n = 2 extra dimensions, particularly neutrino masses and mixing, while also presenting solutions for lepton and quark wave functions in the extra dimensions. The analysis includes assessing issues with flavor-changing neutral-current effects and discussing baryogenesis and dark matter in these models.
Article
Astronomy & Astrophysics
William Giare, Fabrizio Renzi, Olga Mena, Eleonora Di Valentino, Alessandro Melchiorri
Summary: The Data Release 4 of the Atacama Cosmology Telescope (ACT) shows an agreement with a Harrison-Zel'dovich primordial spectrum, introducing a tension with the results from the Planck satellite. This discrepancy on the value of the scalar spectral index is not alleviated with the addition of large scale structure information or low multipole polarization data. Possible avenues to alleviate the tension are discussed, including neglecting polarization measurements from ACT or extending different sectors of the theory.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Thomas Biekoetter, Sven Heinemeyer, Jose Miguel No, Maria Olalla Olea, Georg Weiglein
Summary: Extensions of the Higgs sector of the Standard Model can lead to a rich cosmological history around the electroweak scale, with the possibility of various phenomena such as non-restoration of electroweak symmetry or vacuum trapping. By focusing on the N2HDM of type II and considering theoretical and experimental constraints, scenarios of electroweak symmetry non-restoration, vacuum trapping, and first-order phase transition in the thermal history of the Universe are identified. Despite the presence of a global electroweak minimum in the scalar potential at zero temperature, the physical viability of the N2HDM parameter space is not guaranteed, emphasizing the importance of analyzing tunneling probability for reliable predictions of the Universe's thermal history.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Manuel Gonzalez-Espinoza, Giovanni Otalora, Nelson Videla, Joel Saavedra
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2019)
Article
Physics, Multidisciplinary
Ali Ovgun, Izzet Sakalli, Joel Saavedra
Article
Astronomy & Astrophysics
Ali Ovgun, Izzet Sakalli, Joel Saavedra, Carlos Leiva
MODERN PHYSICS LETTERS A
(2020)
Article
Physics, Nuclear
A. Ovgun, I. Sakalli, J. Saavedra
Article
Physics, Particles & Fields
Manuel Gonzalez-Espinoza, Ramon Herrera, Giovanni Otalora, Joel Saavedra
Summary: This study investigates reconstruction during slow-roll inflation in scalar-torsion theories, exploring a reconstruction scheme to determine the non-minimal coupling function and scalar potential under different parameterizations. Depending on the considered attractors, different expressions for the function F(φ) and potential V(φ) are obtained, along with constraints on model parameters.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
Ramon Becar, P. A. Gonzalez, Joel Saavedra, Yerko Vasquez, Bin Wang
Summary: In this study, black hole solutions to Einstein's theory coupled to a nonlinear power-law electromagnetic field with a fixed exponent value are considered. The extended phase space thermodynamics in canonical and grand canonical ensembles are studied, revealing different types of phase transitions in each ensemble. The research shows that both first- and second-order phase transitions can occur in the canonical ensemble, while Hawking-Page and second-order phase transitions are allowed in the grand canonical ensemble.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2021)
Article
Astronomy & Astrophysics
Almendra Aragon, P. A. Gonzalez, Joel Saavedra, Yerko Vasquez
Summary: In this study, the propagation of scalar fields in 2 + 1-dimensional Coulomb-like AdS black holes is analyzed, demonstrating stability under Dirichlet boundary conditions. By solving the Klein-Gordon equation using various methods, quasinormal frequencies are determined, showing dependence on parameters such as black hole charge, angular number, and overtone number. Additionally, the introduction of a Coulomb-like field from nonlinear electrodynamics to general relativity results in the emergence of two branches of quasinormal frequencies for a null angular number, contrasting with the static BTZ black hole.
GENERAL RELATIVITY AND GRAVITATION
(2021)
Article
Astronomy & Astrophysics
Manuel Gonzalez-Espinoza, Giovanni Otalora, Joel Saavedra
Summary: This study investigates the conditions for eliminating ghost, gradient, and tachyonic instabilities in scalar-torsion f(T, phi) gravity theories, with a general barotropic perfect fluid. By analyzing the gravity and matter sectors separately, it is confirmed that the theory is free from ghost and gradient instabilities, with the propagation speed meeting the standard criteria. The study also provides general expressions for mass eigenvalues in the presence of tachyonic instability, leading to the identification of a parameter space where stable configurations can exist in line with constraints from CMB measurements and BBN. Numerical analysis further supports the stability of the system throughout cosmic evolution.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
P. A. Gonzalez, Eleftherios Papantonopoulos, Joel Saavedra, Yerko Vasquez
Summary: This study considers the propagation of charged massive scalar fields in the background of Reissner-Nordstrom-de Sitter black holes and investigates the effect of the scalar field charge on the spectrum of quasinormal frequencies and the anomalous decay rate. The results show that the anomalous behavior also exists for charged massive scalar fields, and there is a critical value that leads to a reversal of this behavior. Additionally, there is a critical value of the charge parameter and the black hole charge, which increases with the cosmological constant, and beyond this critical value, the anomalous behavior of the decay rate can be avoided for the fundamental mode.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Multidisciplinary
Angel Rincon, P. A. Gonzalez, Grigoris Panotopoulos, Joel Saavedra, Yerko Vasquez
Summary: We investigate the propagation of massless scalar fields non-minimally coupled to gravity in the background of five-dimensional Einstein-Power-Maxwell black holes. By employing the WKB and pseudospectral Chebyshev methods, we calculate the quasinormal frequencies (QNFs), which reveal the existence of stable and unstable QNFs, dependent on the power of nonlinear electrodynamics, the strength of the non-minimal coupling, and the size of the black hole.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
Yoelsy Leyva, Carlos Leiva, Giovanni Otalora, Joel Saavedra
Summary: We study the slow-roll inflation and primordial fluctuations in F(T) gravity's rainbow, and calculate the power spectrum for scalar and tensor perturbations. By comparing the predictions of the model with the current PLANCK and BICEP/Keck data, we verify the results obtained up to first order in slow-roll approximation.
Article
Astronomy & Astrophysics
P. A. Gonzalez, Angel Rincon, Joel Saavedra, Yerko Vasquez
Summary: We study the propagation of charged scalar fields around 2 + 1-dimensional Coulomb-like AdS black holes and find that the quasinormal frequencies (QNFs) are always complex when the scalar field is charged. This is contrary to the uncharged case, where the complex QNFs dominate for small values of the black hole charge and purely imaginary QNFs dominate for larger values.
Article
Astronomy & Astrophysics
Mauricio Cataldo, P. A. Gonzalez, Joel Saavedra, Yerko Vasquez, Bin Wang
Summary: This work investigates the thermodynamics of a (2 + 1)-dimensional static black hole under a nonlinear electric field, including the analysis of black hole thermodynamic geometry and the calculation of heat engine efficiency. The results suggest that the cosmological constant can be considered as an additional extensive thermodynamic variable.
Article
Astronomy & Astrophysics
Shao-Jun Zhang, Bin Wang, Anzhong Wang, Joel F. Saavedra
Article
Astronomy & Astrophysics
Israel Quiros, Tame Gonzalez, Roberto De Arcia, Ricardo Garcia-Salcedo, Ulises Nucamendi, Joel F. Saavedra
