Article
Astronomy & Astrophysics
T. Harko, K. Asadi, H. Moshafi, H. Sheikhahmadi
Summary: This study investigates the effects of interaction, decay, and particle generation in a many-component Universe using an approach based on open system thermodynamics. By introducing particle number balance equations and creation pressures, the cosmological evolution equations are thermodynamically consistent. Constrained by multiple observational data sets, this model provides a solution to the Hubble tension problem.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Physics, Multidisciplinary
Csaba Csaki, Sungwoo Hong, Gowri Kurup, Seung J. Lee, Maxim Perelstein, Wei Xue
Summary: We examine the possibility that dark matter consists of a gapped continuum and propose a continuum model to realize this idea. The model is consistent with observations and has smaller direct detection cross sections compared to ordinary models. The continuum dark matter states decay throughout the history of the Universe and are constrained by observations of cosmic microwave background. Continuum particles produced at colliders exhibit a striking cascade-decay signature.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
James M. Cline, Shan Gao, Fangyi Guo, Zhongan Lin, Shiyan Liu, Matteo Puel, Phillip Todd, Tianzhuo Xiao
Summary: Neutrino emission coinciding with gamma rays has been observed from the blazar TXS 0506 + 056 by the IceCube telescope. These neutrinos had to traverse through a dense spike of dark matter surrounding the central black hole. The observation of such neutrinos implies new upper limits on the neutrino-dark matter scattering cross section as a function of dark matter mass. The constraint is stronger than existing ones for a range of dark matter masses, assuming a linearly rising cross section with energy. Competitive bounds are also possible for constant cross sections, depending on the details of the dark matter spike.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Particles & Fields
Dalibor Perkovic, Hrvoje Stefancic
Summary: Galaxy rotation curves are considered strong evidence for the existence of dark matter or alternative mechanisms. This study presents a model-independent approach to test the hypothesis that dark matter behaves as a barotropic fluid. Using rotation curve data of the Milky Way, constraints on the speed of sound in the barotropic fluid are obtained, demonstrating the potential of this approach. The study also discusses technical challenges, limitations, and possible future extensions and improvements.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Review
Physics, Multidisciplinary
Manuel A. Buen-Abad, Rouven Essig, David McKeen, Yi-Ming Zhong
Summary: This article investigates the effects of dark matter interactions with electrons or protons on the cosmic microwave background and the matter power spectrum, and utilizes diverse data to study these interactions. The study finds that these interactions result in momentum and heat exchange between ordinary and dark matter, and provides constraints on dark matter models. These constraints are crucial for understanding the interactions between dark matter and ordinary matter.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2022)
Article
Multidisciplinary Sciences
Itay M. Bloch, Gil Ronen, Roy Shaham, Ori Katz, Tomer Volansky, Or Katz
Summary: Dark matter, a longstanding mystery in physics, remains unknown in its elementary composition. In this study, we employed a precision quantum detector to search for non-gravitational interactions between axion-like dark matter and atomic spins. By utilizing a spin-polarized xenon gas detector, we were able to observe coherent interactions with the background dark matter field. The results provide improved constraints on the properties of dark matter and its potential interactions with other particles.
Article
Astronomy & Astrophysics
Florian Niedermann, Martin S. Sloth
Summary: Hot new early dark energy is a supercooled phase transition that occurs at sub-eV temperatures in the dark sector. It provides a possible solution to the Hubble tension and explains neutrino masses through the inverse seesaw mechanism.
Article
Astronomy & Astrophysics
Diego Alvarez-Ortega, Gonzalo J. Olmo, Diego Rubiera-Garcia, Diego Saez-Chillon Gomez
Summary: Interacting dark-energy-dark-matter models have been analyzed in an attempt to find traces of new physics. The study shows that by introducing an appropriate coupling, dark-matter observers can see a non beginning, non ending universe, and this type of coupling can fit observational data.
Article
Astronomy & Astrophysics
Guillermo F. Abellan, Riccardo Murgia, Vivian Poulin
Summary: The S-8 tension refers to the discrepancy between the cosmic microwave background (CMB) and weak gravitational lensing determination of matter fluctuations amplitude. A model involving dark matter decay has been proposed to ease this tension, with potential implications for anomalous electron recoil excess reported by the Xenon1T Collaboration. Current CMB data alone may not distinguish between standard cold dark matter and decaying dark matter, but future CMB observations can detect the signature of decaying dark matter.
Article
Physics, Multidisciplinary
Jin-Wei Wang, Alessandro Granelli, Piero Ullio
Summary: We investigate the potential of relativistic protons in the jets of blazars to boost the surrounding dark matter particles to high energies through elastic collisions. By focusing on two sample blazars, namely TXS 0506 + 056 and BL Lacertae, we find that the induced dark matter flux at Earth could be significant and surpasses the flux associated with dark matter boosted by galactic cosmic rays. This becomes relevant for the direct detection of light dark matter particles with masses lighter than 1 GeV, as demonstrated by the null detection of a signal by XENON1T, MiniBooNE, and Borexino.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
Anirban Biswas, Arpan Kar, Hyomin Kim, Stefano Scopel, Liliana Velasco-Sevilla
Summary: Weakly interacting massive particles (WIMPs) in a dark matter-rich environment, such as the core of the Messier 4 globular cluster, can be captured in compact stars like white dwarves (WDs), leading to an increase in the star's luminosity. This study explores the possibility of probing the mass splitting of WIMPs through interactions with nuclear targets within WDs, and applies these findings to the specific scenario of a self-conjugate bidoublet in the left-right symmetric model. The constraints from WDs significantly reduce the viable parameter space of this scenario, requiring certain conditions on the coupling constants.
Article
Astronomy & Astrophysics
Debajit Bose, Tarak Nath Maity, Tirtha Sankar Ray
Summary: By measuring the solar gamma ray flux, we have set stronger limits on the scattering cross section between dark matter and electrons, with these limits ranging from GeV to PeV scale for dark matter masses, which are four to six orders of magnitude stronger than existing limits.
Article
Astronomy & Astrophysics
Trygve Buanes, Inaki Lara, Krzysztof Rolbiecki, Kazuki Sakurai
Summary: We revisit LHC searches for heavy invisible particles using QCD initial state radiation, specifically focusing on the electroweakino sector. By analyzing the dijet signal region in a general multijet plus MET search conducted by ATLAS, we obtain nontrivial mass limits for various models. For instance, winos must have a mass greater than mW > 160 GeV and Higgsinos must have a mass greater than mh > 100 GeV, depending on the chargino-neutralino mass splitting. Furthermore, we predict that the exclusion limits will increase to mW > 200 GeV and mh > 130 GeV for winos and Higgsinos, respectively, with the expected data from LHC Run 3 with L = 300 fb-1. This study presents the first LHC limit for promptly decaying nearly mass-degenerate winos.
Article
Astronomy & Astrophysics
M. Sten Delos, Gabriele Franciolini
Summary: Cosmological observations provide precise measurements of density variations in the Universe, but smaller scales are still poorly understood. This study investigates the formation and detection of ultradense dark matter minihalos, which can lead to detectable microlensing signatures. The results suggest that current data may already constrain the primordial curvature perturbations and future data can further enhance these constraints.
Article
Astronomy & Astrophysics
Umberto Maio, Matteo Viel
Summary: In this study, the implications of the latest JWST data on the nature of dark matter are investigated. High-redshift galaxies observed by JWST are compared with hydrodynamical simulations in both the standard cold dark matter model and warm dark matter models with a suppressed linear matter power spectrum. The results show that the current data are consistent with both cold dark matter and warm dark matter models with m(WDM) > 2 keV.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Physics, Nuclear
J. C. Fabris, T. R. P. Carames, A. Wojnar, H. E. S. Velten
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2020)
Article
Physics, Multidisciplinary
Julio C. Fabris, Tales Gomes, Junior D. Toniato, Hermano Velten
Summary: The paper presents a Lagrangian formulation for a varying G Newtonian-like theory inspired by Brans-Dicke gravity. Instead of imposing an ad hoc dependence for the gravitational coupling, the running of G emerges naturally from the internal dynamical structure of the theory. The features of the resulting gravitational field for static and spherically symmetric mass distributions as well as within the cosmological framework are explored.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Editorial Material
Astronomy & Astrophysics
Hermano Velten, Giuseppe Dito
Review
Astronomy & Astrophysics
Hermano Velten, Thiago R. P. Carames
Summary: Extended theories of gravity beyond the conservative framework of general relativity have become popular in recent years, aiming to describe the phenomenology of dark matter and dark energy. While many of these theories attempt to preserve the conservative property of the energy-momentum tensor, some unavoidably have non-trivial conservation laws as part of their structure when no extra constraint is available.
Article
Multidisciplinary Sciences
Julio C. Fabris, Marcelo H. Alvarenga, Mahamadou Hamani Daouda, Hermano Velten
Summary: Unimodular gravity is a gravity theory characterized by an extra condition compared to general relativity. The symmetry properties of unimodular gravity are governed by transverse diffeomorphisms, and in the case of nonconservation, gravitational waves are strongly amplified.
Article
Astronomy & Astrophysics
Alexandre M. R. Almeida, Julio C. Fabris, Mahamadou Hamani Daouda, Richard Kerner, Hermano Velten, Willian S. Hipolito-Ricaldi
Summary: This paper introduces a unimodular version of the Brans-Dicke theory with a constrained Lagrangian formulation, resulting in traceless field equations. The vacuum solutions in the cosmological background reproduce the solutions of the usual Brans-Dicke theory with an additional cosmological constant term. A perturbative analysis of the scalar modes reveals both stable and unstable configurations, contrasting with the Brans-Dicke case where only stable configurations occur. However, the tensorial modes remain unchanged in this theory compared to the traditional Brans-Dicke theory.
Article
Astronomy & Astrophysics
Nicolas R. Bertini, Hermano Velten
Summary: The f(R, T) gravity is a model that contains an arbitrary function of the Ricci scalar R and the trace of the energy-momentum tensor T in its action. By analyzing the dynamical equations for perfect fluids, it is determined how the function & phi; depends on T, regardless of the equation of state and geometry of the matter fields. The analysis of the parametrized post-Newtonian (PPN) formalism shows that the linear dependence of & phi; on T is severely constrained.
Article
Astronomy & Astrophysics
Diego Santos de Jesus, Hermano Velten, Federico Piazza
Summary: In this paper, we revisit the decay of the orbital period in binary systems caused by the emission of gravitational waves, considering modified gravity models where the coupling Ggw between matter and on shell gravitons differs from the Newton constant GN. By using the double pulsar, the most precisely-timed double neutron star binary system, we constrain the ratio Ggw=GN to the level of 10-4, improving the present bound on this quantity by two orders of magnitude.
Article
Physics, Multidisciplinary
Felipe S. Escorcio, Julio C. Fabris, Junior D. Toniato, Hermano Velten
Summary: This article proposes a Newtonian-like theory inspired by the Brans-Dicke gravitational Lagrangian, which can explain the problem of the perihelion advance of Mercury and constrain the free parameter of the theory through predicted expressions.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Raquel Emy Fazolo, Luca Amendola, Hermano Velten
Summary: This study investigates the role of dark energy perturbations in the skewness S-3 of large-scale matter distribution. A two-fluid universe composed of matter and dark energy, with perturbations in both components, is considered. The skewness of the matter density field is numerically estimated as a function of the dark energy parameters. The study characterizes the S-3 value for quintessence and phantom dark energy cosmologies, and its dependence on the matter density parameter and the dark energy sound speed, providing accurate numerical fitting. These fits can be used to test cosmology against future high-quality data on large-scale structure.
Article
Physics, Multidisciplinary
Julio C. Fabris, Tulio Ottoni, Junior D. Toniato, Hermano Velten
Summary: A Newtonian-like theory inspired by the Brans-Dicke gravitational Lagrangian has been proposed, where the gravitational coupling acquires spatial dependence within the matter distribution. This theory can provide a testable environment within astrophysical configurations and has an impact on the physical properties of stars.
Article
Astronomy & Astrophysics
Hermano Velten, Ingrid Costa, Winfried Zimdahl
Summary: Studying an expanding two-fluid model of nonrelativistic dark matter and radiation, researchers found the existence of transient bulk viscosity has significant impacts on tensions in the standard cosmological model, particularly on the H-0 and S-8 values.
Article
Astronomy & Astrophysics
Hermano Velten, Syrios Gomes
Article
Astronomy & Astrophysics
Hermano Velten, Raquel Emy Fazolo
Article
Astronomy & Astrophysics
Julio C. Fabris, Hermano Velten, Aneta Wojnar
