Article
Astronomy & Astrophysics
Torsten Bringmann, Paul Frederik Depta, Marco Hufnagel, Joern Kersten, Joshua T. Ruderman, Kai Schmidt-Hoberg
Summary: We propose a new mechanism for generating undetectable sterile neutrinos vs in the early Universe, through the conversion of ordinary neutrinos va in scattering processes vsva -> vsvs. This leads to an exponential growth in the abundance of vs after initial production by oscillations. We demonstrate that this production regime occurs naturally for self-interacting vs, offering significant opportunities for vs to account for all observed dark matter. Our findings provide strong motivation to enhance the sensitivity of X-ray line searches and improve constraints from structure formation.
Article
Astronomy & Astrophysics
Wonsub Cho, Ki-Young Choi, Osamu Seto
Summary: We consider the possibility of the lightest sterile neutrino being the dark matter candidate, with a dipole interaction with heavier sterile neutrinos. We find that a light sterile neutrino in the MeV range, with a dimension-five nonrenormalizable dipole interaction suppressed by ?5 greater than or similar to 1015 GeV, can be a good dark matter candidate, while heavier sterile neutrinos in the GeV range can explain active neutrino oscillations.
Article
Physics, Particles & Fields
Ang Liu, Feng-Lan Shao, Zhi-Long Han, Yi Jin, Honglei Li
Summary: In this paper, a model of sterile neutrino portal dark matter in vTHDM is proposed. This model can naturally generate tiny neutrino mass with the neutrinophilic scalar doublet (I)v and sterile neutrinos N around TeV scale. a Z2 symmetry, a Dirac fermion singlet x and a scalar singlet 0 are introduced in the dark sector. The sterile neutrinos N act as mediators between the DM and SM. Depending on the coupling strength, the DM can be either WIMP or FIMP. The key channel for the WIMP scenario is the pair annihilation of DM into N N, which can be tested at indirect detection experiments. For the FIMP scenario, besides the direct production of DM from freeze-in mechanism, contributions from late decay of NLOP are also important. When sterile neutrinos are heavier than the dark sector, NLOP is long-lived due to tiny mixing angle between sterile and light neutrinos. Constrains from free streaming length, CMB, BBN and neutrino experiments are considered.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Carlos Jaramillo
Summary: This paper proposes a new production mechanism for keV sterile neutrino dark matter, which relies on thermal freeze-out to produce dark matter neutrinos. The challenge lies in balancing large and small Yukawa couplings to ensure the thermalization and stability of sterile neutrinos. This problem is solved by implementing varying Yukawa couplings. The interplay of seesaw and Froggatt-Nielsen mechanisms explains the hierarchy in the flavour structure and the origin of light neutrino masses.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Kevin J. Kelly, Manibrata Sen, Yue Zhang
Summary: The self-interacting neutrino hypothesis provides motivation for addressing the tension between the origin of sterile neutrino dark matter and indirect detection constraints, and can produce a variety of testable signals from laboratories to the cosmos. In certain models, there must be a lower bound on the amount of extra radiation in the early Universe, which will be further strengthened with an improved x-ray search at the Athena observatory. This intimate relationship will be unambiguously tested by the upcoming CMB Stage 4 project.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Rui An, Vera Gluscevic, Ethan O. Nadler, Yue Zhang
Summary: Sterile neutrinos only interact with the standard model through the neutrino sector, making them a simple dark matter candidate. Recently, there has been attention on sterile neutrinos produced through self-interactions of active neutrinos as a particle candidate that can explain the observed dark matter relic abundance without violating constraints from X-ray observations. In this study, the consistency of this production mechanism with the abundance of small-scale structure in the universe, as represented by the population of ultrafaint dwarf galaxies orbiting the Milky Way, is examined. A lower bound on the sterile-neutrino particle mass of 37 keV is derived, and it is found that strong neutrino self-coupling mediated by a heavy scalar is excluded while production via a light mediator is still possible.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Hooman Davoudiasl, Peter B. Denton
Summary: This study proposes a cosmologically viable proposal that is consistent with terrestrial experiments and solar constraints, by sourcing the mass of unobservable sterile neutrinos with a mass of -1 eV from an ultralight scalar field Φ. In this scenario, the experimentally implied -1 eV sterile neutrino mass is a local value and changes throughout spacetime.
Article
Astronomy & Astrophysics
Sho Iwamoto, Karoly Seller, Zoltan Trocsanyi
Summary: This study explores the parameter space of a U(1) extension of the standard model, known as the super-weak model, in order to explain the observed dark matter energy density. The results reveal regions in the super-weak coupling vs. the mass of the new gauge boson plane that are not excluded by current experimental constraints, indicating the importance of further investigation into the freeze-out mechanism for dark matter production.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Alberto Salvio, Simone Scollo
Summary: Extending the standard model with three right-handed neutrinos and a simple QCD axion sector can account for various phenomena, but in this model, dark matter does not originate from primordial black holes, but rather consists of a multi-component axion-sterile neutrino composition.
Article
Physics, Particles & Fields
Shao-Feng Ge, Pedro Pasquini, Jie Sheng
Summary: The recent XENON1T excess can be explained by the solar active-sterile neutrino conversion with bound electrons via light mediator. However, the atomic effects are usually ignored in the solar neutrino explanations. We establish a second quantization formalism to account for the atomic effects, showing that they can have a significant impact on the cross section. It is necessary to include atomic effects in dark matter direct detection experiments for both low-energy electron recoil signals and energetic solar neutrinos.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Gonzalo Alonso-Alvarez, James M. Cline
Summary: Sterile neutrinos that mix with active neutrinos are considered as interesting dark matter candidates, with their production being constrained by structure formation observations and X-ray searches. Resonant oscillations between active and sterile neutrinos can occur in the early universe if active neutrinos couple to an oscillating condensate of a very light gauge field, allowing sterile neutrinos to potentially make up all of the dark matter while respecting X-ray constraints. These deviations from standard neutrino oscillations could still be present today.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Marco Nikolic, Suchita Kulkarni, Josef Pradler
Summary: In this work, we analyze the ultimate sensitivity of dark matter direct detection experiments to dark radiation, either in the form of Standard Model (SM) or semi-sterile neutrinos. We find that xenon-based dark matter searches will not be able to probe new regions of the dark matter progenitor mass and lifetime parameter space when the decay products are SM neutrinos. However, if the decay happens to a fourth neutrino species with enhanced interactions to baryons, dark radiation can either constitute the dominant background or a discoverable signal in direct detection experiments.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Adam Duran, Logan Morrison, Stefano Profumo
Summary: The study generalizes the production of gravitational particles in a radiation-dominated, CPT-symmetric universe to nonstandard but also CPT-symmetric early-Universe cosmologies. Calculations were made to determine the necessary mass for a right-handed sterile neutrino to be cosmological dark matter. Additionally, state-of-the-art tools were utilized to compute the expected spectra of gamma rays and high-energy active neutrinos resulting from the decay of ultraheavy sterile neutrino dark matter. The research shows that the sterile neutrinos were never in thermal equilibrium in the early Universe and discusses the potential detection of signals for varying sterile neutrino lifetimes.
Article
Astronomy & Astrophysics
Andrea Gaspert, Pietro Giampa, David E. Morrissey
Summary: Experiments using liquid noble gases like argon and xenon are crucial for detecting weakly interacting massive particles as dark matter. However, as these experiments scale up, they will face new backgrounds from neutrino scattering. By combining data from independent argon and xenon experiments, significant improvements in sensitivity can potentially be achieved in large-scale experiments.
Article
Astronomy & Astrophysics
Lucia Aurelia Popa
Summary: Constraints are placed on dark matter sterile neutrino scalar decay production, with results indicating that the mass fraction and mass of the sterile neutrino within the co-moving free-streaming horizon are constrained. The datasets used in the analysis provide sensitivity to these parameters and are in agreement with experimental observations.
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.