Article
Astronomy & Astrophysics
Mar Bastero-Gil, Jose Santiago, Roberto Vega-Morales, Lorenzo Ubaldi
Summary: We study a mechanism for producing dark photon dark matter at the end of inflation. The rolling inflaton induces a tachyonic instability, leading to the coherent production of dark gauge bosons. We examine the case where the dark photons are relativistic when their mass is generated and calculate the relic abundance today. Furthermore, we analyze the late time power spectrum and find that it preserves the peak generated at the end of inflation.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Federico Compagnin, Stefano Profumo, Nicolao Fornengo
Summary: This article investigates the cosmology and phenomenology of a dark photon portal with a simple dark sector composed of a single, light, fermionic dark matter particle species with mass in the MeV range. Three possible kinetic mixing structures between a new Abelian gauge group U(1)dark and the visible sector are considered: U(1)e.m., U(1)Y, and T[SU(2)L]. The author assumes the dark photon to have a massive and MeV-scale mass, close to the mass scale of the dark matter candidate. The article calculates the dark matter relic density through freeze-out and freeze-in, taking into account the possibility of a late inflationary period that could dilute the dark matter yield of heavy candidates and additional production modes for models with under-abundant thermal production. The parameter space compatible with various experimental and astrophysical constraints is explored, and prospects for discovery using new CMB probes and MeV gamma-ray telescopes are discussed.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
J. A. Aguilar-Saavedra, D. E. Lopez-Fogliani, C. Munoz, M. Pierre
Summary: The study introduces the U mu nu SSM model as an extension of the mu nu SSM supersymmetric model, where violating baryon-number operators and explicit mass terms are prohibited. The research also analyzes the relic density of the dark matter candidate by calculating through Z', Higgs-right sneutrino, and dark matter mediated annihilations, as well as assessing potential signals in dark matter direct detection experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sven Baumholzer, Vedran Brdar, Enrico Morgante
Summary: In this study, structure formation limits on dark matter composed of keV-scale axion-like particles are derived, with a focus on freeze-in production through interactions with photons and SM fermions. The results show that for the photophobic ALP scenario, where DM primarily couples to SM fermions, weaker constraints on DM mass can be obtained, indicating potential for a wider range of mass values. Future facilities like the Vera C. Rubin observatory are expected to significantly improve current bounds on DM mass, potentially reaching up to 80 keV.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Lei Zu, R. Foot, Yi-Zhong Fan, Lei Feng
Summary: The study investigates the possibility of dark matter in the form of a dark plasma in the Milky Way halo, interacting with ordinary matter and producing signals in dark matter direct detection experiments. The observed excess in the XENON1T experiment can be explained with kinetic mixing in a specific range, consistent with astrophysical and cosmological constraints and other direct detection experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Talal Ahmed Chowdhury, Shaikh Saad
Summary: Expanding the Standard Model with a non-Abelian gauge symmetry can explain the muon anomalous magnetic moment and reproduce the correct relic abundance, but concurrently describing the electron anomalous magnetic moment in this setup is challenging.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Lam Hui, Austin Joyce, Michael J. Landry, Xinyu Li
Summary: The interference of waves in galactic halos inevitably leads to the formation of vortices, which exhibit universal features such as taking the form of vortex rings in three spatial dimensions and typically containing only single winding vortices in realistic scenarios. The density near a vortex scales as r(2) while the velocity goes as 1/r, and smaller vortex rings move faster due to their curvature scale. Observational and experimental signatures from these vortices and wave interference include gravitational lensing leading to flux anomalies in strongly lensed systems, as well as potential signal diminishment in detection experiments for QCD axions. We also propose the measurement of correlation functions by axion detection experiments to probe and utilize the expected interference substructures.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yann Mambrini, Keith A. Olive, Jiaming Zheng
Summary: Dark matter may only interact with the visible sector at high energy scales. During the period of reheating, the dominant process of dark matter production is through the decay products of the inflaton. This process dominates for low reheating temperatures and can produce the required density of dark matter.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Logan Morrison, Stefano Profumo, Dean J. Robinson
Summary: The study discusses a dark QCD sector as a minimal extension of the Standard Model, which includes Dark Matter candidates without the need for additional interactions with the visible sector. Under specific conditions, this dark sector can generate Dark Matter candidates.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Shao-Ping Li, Xun-Jie Xu
Summary: We investigate the production of dark matter (DM) from right-handed neutrinos (RHNs) in the context of a dark sector connected to the standard model via RHNs. Our study focuses on a simple and generic interaction between RHNs and a pair of dark particles. Depending on the mass of RHNs and their freeze-in/out status, different scenarios with distinct results are considered. We conduct a comprehensive and systematic study of all possible scenarios and apply our results to the type-I seesaw model with a dark sector extension to examine the freeze-in/out regime of DM. Some observational consequences in this framework are discussed as well.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Wasif Husain, Anthony W. Thomas
Summary: This study examines neutron star models with dark matter in the core, investigating properties of different types of dark matter particles and their interactions. Constraints on mass, radius, and tidal deformability are considered, along with the distribution of energy density inside the stars. The presence and behavior of fermionic dark matter throughout the star is particularly noted.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Johannes Herms, Alejandro Ibarra
Summary: This study investigates a dark matter scenario containing two generations of dark matter particles with different masses and couplings. In some parts of the parameter space, the heavier generation of dark matter can play a pivotal role in generating the correct dark matter abundance. This can lead to significantly boosted indirect and direct detection signals compared to scenarios with only single-flavored dark matter.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Oleg Lebedev
Summary: Stable scalars can be abundantly produced in the Early Universe even without coupling to other fields. The production and mass scale of these scalars during and after (high scale) inflation are studied, leading to strong constraints. Quantum gravity-induced Planck-suppressed operators significantly affect the abundance of dark matter relics, often resulting in overproduction unless the corresponding Wilson coefficients are very small. The uncontrollable nature of these effects without a quantum gravity theory questions the predictability of many non-thermal dark matter models and has potential implications for string theory constructions with abundant scalar fields.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Seyong Kim, M. Laine
Summary: Recently, there have been questions regarding how kinetic equilibrium is maintained when freeze-out dynamics is pushed to low temperatures in the context of the scalar singlet dark matter model with a mass of 60 GeV. Langevin simulations are used to address the non-equilibrium momentum distribution of non-relativistic particles in a cosmological background. These simulations suggest that kinetic equilibrium is a good approximation down to temperatures around 1 GeV for scalar singlet masses below 60 GeV, with deviations appearing as a red-tilted spectrum. This confirms that a slightly larger coupling than in equilibrium is needed to obtain the correct abundance, reducing the annihilation cross section.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Paola Arias, Dimitrios Karamitros, Leszek Roszkowski
Summary: The study examines dark matter production through freeze-in, considering the effects of a dominating fluid in the early Universe before entropy injection. It highlights the alterations in the Universe's expansion rate and temperature scaling, impacting the evolution of dark matter particle characteristics. The findings suggest that enhanced dark matter production rates are needed relative to standard cosmology due to entropy injection effects, potentially influencing constraints on dark matter mass from structure formation data.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
F. Darabi, Y. Heydarzade, F. Hajkarim
CANADIAN JOURNAL OF PHYSICS
(2015)
Article
Astronomy & Astrophysics
Manuel Drees, Fazlollah Hajkarim
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
Article
Physics, Particles & Fields
Mohsen Khodadi, Kourosh Nozari, Fazlollah Hajkarim
EUROPEAN PHYSICAL JOURNAL C
(2018)
Article
Physics, Particles & Fields
Manuel Drees, Fazlollah Hajkarim
JOURNAL OF HIGH ENERGY PHYSICS
(2018)
Article
Astronomy & Astrophysics
Nicolas Bernal, Anish Ghoshal, Fazlollah Hajkarim, Gaetano Lambiase
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Physics, Multidisciplinary
Volodymyr Vovchenko, Bastian B. Brandt, Francesca Cuteri, Gergely Endrodi, Fazlollah Hajkarim, Juergen Schaffner-Bielich
Summary: By investigating the potential formation of a Bose-Einstein condensed phase of pions in the early Universe, it is found that the cosmic trajectory can pass through the pion condensed phase when the combined electron and muon asymmetry is sufficiently large. Future studies will be able to confirm or rule out the condensation of pions, as well as reveal the impact of the pion condensed phase on the spectrum of primordial gravitational waves and the mass distribution of primordial black holes.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Particles & Fields
Soroush Shakeri, Fazlollah Hajkarim, She-Sheng Xue
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Physics, Particles & Fields
Francesco D'Eramo, Fazlollah Hajkarim, Seokhoon Yun
Summary: This passage discusses thermal axion production in the early universe, focusing on mass thresholds and the resulting rate changes. It provides a systematic analysis of production across thresholds in the KSVZ and DFSZ frameworks, addressing cosmological implications and the potential discovery reach of future CMB-S4 surveys.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Francesco D'Eramo, Eleonora Di Valentino, William Giare, Fazlollah Hajkarim, Alessandro Melchiorri, Olga Mena, Fabrizio Renzi, Seokhoon Yun
Summary: In this study, the joint constraints in the mixed hot dark matter scenario were revisited to provide updated bounds on axion and neutrino masses. By avoiding approximate methods and limitations, robust and self-consistent limits were obtained. Future observations are expected to improve the constraints on the axion mass.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Soroush Shakeri, Fazlollah Hajkarim
Summary: In this article, the impact of axion-like particles on the light polarization around the horizon of supermassive black hole (SMBH) is discussed based on the latest polarization measurement of the Event Horizon Telescope (EHT). The different sources of polarization due to axion interaction with photons and the magnetic field of SMBH are investigated, which can modify the linear and circular polarization parameters of the emitted light. It is shown that significant circular polarization can be produced via photon scattering from the background magnetic field with axions as off-shell particles, further constraining the parameter space of ultralight axion-like particles and their couplings with photons. Future precise measurements of circular polarization can probe the features of ultralight axions in the near vicinity of SMBH.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Nicolas Bernal, Fazlollah Hajkarim, Yong Xu
Summary: This study investigates the production of QCD axion dark matter in a nonstandard cosmological era caused by primordial black holes. It explores the impact of primordial black holes on dark matter produced via the misalignment mechanism. The evaporation of primordial black holes injects entropy into the standard model, diluting the originally produced axion relic abundance.
Article
Astronomy & Astrophysics
Fazlollah Hajkarim, Juergen Schaffner-Bielich
Article
Astronomy & Astrophysics
Nicolas Bernal, Fazlollah Hajkarim
Article
Astronomy & Astrophysics
Fazlollah Hajkarim, Juergen Schaffner-Bielich, Stephan Wystub, Mandy M. Wygas