Constituents Of Dark Matter Research Articles

Enhanced monochromatic photon emission from millicharged co-interacting dark matter

We study a millicharged co-interacting dark matter scenario, where the primary dark matter constituent is the dark photon A′ and the secondary component is the fermion χ. In this model, χ interacts with A′ via a U(1)′ interaction while being millicharged with respect to normal photons. Our investigation focuses on the oscillation of A′ dark matter into photons within the background of χ particles, revealing that the A′ − χ scattering rate benefits from a Bose enhancement of the A′ final state. As the oscillation production rate is directly linked to the scattering rate, the conversion of A′ dark matter into monochromatic photons experiences significant amplification owing to this Bose enhancement, especially when the scattering rate Γsca approaches the dark photon mass mA′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_{A^{\\prime }} $$\\end{document}. These converted monochromatic photons are detectable through radio telescopes and can induce distortions in the Cosmic Microwave Background (CMB) spectrum. We find that the sensitivity of radio telescopes and the constraints imposed by CMB distortion on the kinetic mixing parameter are notably heightened compared to scenarios without the subdominant millicharged dark matter.

Theoretical WIMP–Nucleus Scattering Rates for Isomeric Nuclei

The direct detection of dark matter constituents, particularly weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper, we develop the formalism for WIMP–nucleus-induced transitions from isomeric nuclear states, with particular focus on the experimentally interesting target 180Ta.

Single-epoch and Differential Astrometric Microlensing of Quasars

We propose and discuss a new experimental approach to measure the centroid shift induced by gravitational microlensing in the images of lensed quasars (astrometric microlensing). Our strategy is based on taking the photocenter of a region in the quasar large enough as to be insensitive to microlensing as reference to measure the centroid displacement of the continuum. In this way, single-epoch measurements of astrometric microlensing can be performed. Using numerical simulations, we show that, indeed, the centroid shift monotonically decreases as the size of the emitting region increases, and only for relatively large regions, like the broad line region (BLR), does the centroid shift become negligible. This opens interesting possibilities to study the stratification of the different emitters in the accretion disk and the BLR. We estimate the amplitude of the centroid shifts for 79 gravitationally lensed images and study more thoroughly the special cases Q2237+030 A, RXJ1131-1231 A, PG1115+080 A2, and SDSS J1004+4112 A. We propose to use spectro-astrometry to simultaneously obtain the photocenters of the continuum and of different emission line regions since, with the precision of forthcoming instruments, astrometric microlensing by ∼1 M ⊙ mass microlenses may be detected in many quasar lensed images. When we consider more massive micro/millilenses, M ≳ 10 M ⊙, often proposed as the constituents of dark matter, the BLR becomes sensitive to microlensing and can no longer be used as a positional reference to measure centroid shifts. Differential microlensing between the images of a lensed quasar along several epochs should be used instead.

Direct WIMP detection rates for transitions in isomeric nuclei

The direct detection of dark matter constituents, in particular the weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper we study WIMP induced transitions from isomeric nuclear states for two possible isomeric candidates: Ta180 and Ho166. The experimental setup, which can measure the possible decay of Ta180 induced by WIMPs, was proposed. The corresponding estimates of the half-life of Ta180 are given in the sense that the WIMP-nucleon interaction can be interpreted as ordinary radioactive decay.

Testing Primordial Black Hole Dark Matter with Atacama Large Millimeter Array Observations of the Gravitational Lens B1422+231

We examine the flux density ratio anomaly in the quadruply imaged strong gravitational lens, B1422+231, and consider the contribution of 10–103M⊙ primordial black holes (PBHs) as a potential dark matter constituent. We describe the first flux density ratio measurement of B1422+231 in the millimeter-wave band using the Atacama Large Millimeter Array (ALMA). The flux density of the quasar at 233 GHz is dominated by synchrotron emission and the source size is estimated to be less than 66.9 pc. The observed flux density ratios at 233 GHz are similar to those measured in other wave bands, which cannot be explained by a simple smooth mass model of the lens galaxy. We examine the probability of the flux density ratio anomaly arising from PBH microlensing using ray tracing simulations. The simulations consider the cases where 10% and 50% of dark matter are 10–103M⊙ PBHs with a power law mass function. The simulated scenarios are consistent with the ALMA observations, so PBH dark matter cannot be ruled out as a cause of flux density ratio anomalies. Our analysis shows that the anomalous flux density ratio for B1422+231 can be explained by a lens model with a significant fraction of dark matter being PBHs. This study demonstrates the potential for new constraints on PBH dark matter using ALMA observations of multiply imaged strong gravitational lenses.

Full analysis of the scalar-induced gravitational waves for the curvature perturbation with local-type non-Gaussianities

Abstract Primordial black holes (PBHs) are supposed to form through the gravitational collapse of regions with large density fluctuations. The formation of PBHs inevitably leads to the emission of scalar-induced gravitational wave (SIGW) signals, offering a unique opportunity to test the hypothesis of PBHs as a constituent of dark matter (DM). Previous studies have calculated the energy spectrum of SIGWs in local-type non-Gaussian models, primarily considering the contributions from the F NL-order or the G NL-order while neglecting connected diagrams. In this study, we extend the previous work by (i) considering the full contribution of non-Gaussian diagrams up to the G NL-order; (ii) deriving the generic scaling of the SIGW energy spectrum in the infrared region. We derive semi-analytical results applicable to arbitrary primordial power spectra and numerically evaluate the energy spectrum of SIGWs for a log-normal power spectrum.

Revealing dark matter dress of primordial black holes by cosmological lensing

Stellar-mass primordial black holes (PBHs) from the early Universe can directly contribute to the gravitational wave (GW) events observed by LIGO, but can only comprise a subdominant component of the dark matter (DM). The primary DM constituent will generically form massive halos around seeding stellar-mass PBHs. We demonstrate that gravitational lensing of sources at cosmological (≳Gpc) distances can directly explore DM halo dresses engulfing PBHs, challenging for lensing of local sources in the vicinity of Milky Way. Strong lensing analysis of fast radio bursts detected by CHIME survey already starts to probe parameter space of dressed stellar-mass PBHs, and upcoming searches can efficiently explore dressed PBHs over ∼10−105M⊙ mass-range and provide a stringent test of the PBH scenario for the GW events. Our findings establish a general test for a broad class of DM models with stellar-mass PBHs, including those where QCD axions or WIMP-like particles comprise predominant DM. The results open a new route for exploring dressed PBHs with various types of lensing events at cosmological distances, such as supernovae and caustic crossings.

Dark Matter phenomenology in 2HDMS

The constituents of dark matter are still an unresolved puzzle. Several Beyond Standard Model (BSM) Physics offer suitable candidates. In this study here we consider the Two Higgs Doublet model augmented with a complex scalar singlet (2HDMS) and focus on the dark matter phenomenology of 2HDMS with the complex scalar singlet as the dark matter candidate. The parameter space allowed from existing experimental constraints from dark matter, flavour physics and collider searches has been studied. The discovery potential for such a 2HDMS at HL-LHC and at future e^+e^-e+e− colliders has been worked out.

Laboratory Constraints on the Neutron-Spin Coupling of feV-Scale Axions

A new analysis methodology of K-${}^{3}$He comagnetometer data provides vastly improved constraints on axion neutron-spin coupling, shrinking the parameter search space for this proposed constituent of dark matter.

Unifying baryogenesis with dark matter production

We here propose a mechanism that predicts, at early times, both baryon asymmetry and dark matter origin and that recovers the spontaneous baryogenesis during the reheating. Working with U(1)-invariant quark Q and lepton L effective fields, with an interacting term that couples the evolution of Universe’s environment field $$\psi $$ , we require a spontaneous symmetry breaking and get a pseudo Nambu–Goldstone boson $$\theta $$ . The pseudo Nambu–Goldstone boson speeds the Universe up during inflation, playing the role of inflaton, enabling baryogenesis to occur. Thus, in a quasi-static approximation over $$\psi $$ , we impressively find both baryon and dark matter quasi-particle production rates, unifying de facto the two scenarios. Moreover, we outline particle mixing and demonstrate dark matter takes over baryons. Presupposing that $$\theta $$ field energy density dominates as baryogenesis stops and employing recent limits on reheating temperature, we get numerical bounds over dark matter constituent, showing that the most likely dark matter would be consistent with MeV-scale mass candidates. Finally, we briefly underline our predictions are suitable to explain the the low-energy electron recoil event excess between 1 and 7 keV found by the XENON1T collaboration.

Phenomenological implications of the new Littlest Higgs model with T-parity

We investigate the parameter space of the new Littlest Higgs model with T-parity (NLHT) recently introduced to cure some pathologies of the original LHT. The model requires extra fermion content and additional pseudo-Goldstone bosons. While the heavy top quark sector is similar, there are both T-odd and T-even heavy quarks and leptons with masses proportional to just two sets of Yukawa matrices in flavor space, one more than in the LHT. The new scalars are a singlet and real triplet, T-odd, with masses controlled by gauge and Yukawa couplings, independent of the spontaneous symmetry breaking scale f, and hence potentially light. Imposing that no mass exceeds the cutoff scale, applying current lower bounds on vector-like quarks and assuming a simplified model with mass degenerate heavy fermions compatible with the heavy photon as dark matter constituent, we find that f gets constrained within the interval between 2 and 3 TeV, the common Yukawa coupling of heavy leptons gets fixed and the Yukawa coupling of heavy quarks becomes greatly correlated to the top quark Yukawa couplings. The particle spectrum is then bounded from below and above, with the (lightest) heavy photon at about 0.5 TeV, not far from the heavy leptons, the new scalars below 1 TeV, the usual complex scalar triplet close to the heavy weak bosons at about 1.5 to 2.5 TeV, and the heavy quarks and top quark partners between 2 and 5 TeV. The new scalars decay predominantly to a standard and a T-odd lepton and have a width comparable to that of the Higgs.

Dark Matter direct detection of classical WIMPs

One of the highest priorities in particle physics today is the identification of the constituents of dark matter. This manuscript is a supplement to pedagogical lectures given at the 2021 Les Houches Summer School on Dark Matter. The lectures cover topics related to the direct detection of Weakly Interaction Massive Particle (WIMP) dark matter, including the distribution of dark matter, nuclear scattering, backgrounds, planning and designing of experiments, and a sampling of planned and ongoing experiments.

Bifurcated symmetry breaking in scalar-tensor gravity

We present models that simultaneously predict the presence of dark energy and cold dark matter along with slow-roll inflation. The dark energy density is found to be of order $(\text{a few meV}{)}^{4}$, and the mass of dark matter constituent is $\ensuremath{\approx}1\text{ }\text{ }\mathrm{meV}$. These numbers are given in terms of the present value of Hubble constant ${H}_{0}$ and the Plank energy ${M}_{\mathrm{P}}\text{ }=\text{ }1/\sqrt{16\ensuremath{\pi}{G}_{N}}$: they are $({H}_{0}{M}_{\mathrm{P}}{)}^{2}$ for the dark energy density and $({H}_{0}{M}_{\mathrm{P}}{)}^{1/2}$ for the dark matter constituent mass. The basic theoretical framework we work in is a multiscalar tensor gravity with nontrivial conformal coupling to the Ricci scalar curvature in the Lagrangian density. The key for a right amount of dark energy is to incorporate in a novel way the spatially homogeneous kinetic contribution of Nambu-Goldstone modes in a spontaneously broken multiscalar field sector. Proposed theories are made consistent with general relativity tests at small cosmological distances, yet are different from general relativity at cosmological scales. Dark matter is generated as a spatially inhomogeneous component of the scalar system, with a roughly comparable amount to the dark energy. In some presented models a cosmological bifurcation of symmetry breaking of the scalar sector is triggered by the spontaneous breaking of electroweak $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ gauge symmetry, hence the separation occurring simultaneously at the electroweak phase transition. The best experimental method to test presented models is to search for the fifth-force type of scalar exchange interaction with a force range, $O({10}^{\ensuremath{-}2})\text{ }\text{ }\mathrm{cm}$, whose coupling to matter is basically of gravitational strength.

Limiting the Abundance of LIGO/Virgo Black Holes with Microlensing Observations of Quasars of Finite Size

We present a simple but general argument that strongly limits the abundance of primordial black holes (PBHs) (or other unknown population of compact objects) with masses similar to those determined by LIGO/Virgo from BH binary mergers. We show that quasar microlensing can be very sensitive to the mass of the lenses, and that it is able to distinguish between stars and BHs of high mass, when the finite size of the source is taken into account. A significant presence of massive BHs would produce frequent high-flux magnifications (except for unrealistically large sources), which have been very rarely observed. On the contrary, a typical stellar population would induce flux magnifications consistent with the observations. This result excludes PBHs (or any type of compact object) in the mass range determined by LIGO/Virgo as the main dark matter constituents in the lens galaxies.

Neutrino interactions with ultralight axion-like dark matter

In this work, we study the propagation of high energy neutrinos produced in extragalactic sources including the effect of a possible interaction with ultralight axion-like particles (UALP) with a mass m_asim 10^{-22} ,mathrm{eV} as the constituents of dark matter (DM) under the assumption that their coupling to neutrinos is dominant. We compute the cross section and describe the propagation of a diffuse neutrino flux using transport equations for each mass eigenstate. This allows us to obtain the neutrino fluxes of the different flavors to be observed at the Earth with neutrino telescopes under different assumptions for the flavor composition emitted at the sources and for a normal ordering (NO) or an inverted ordering (IO) of the neutrino masses. If the coupling of neutrinos with UALPs is the same for all flavors (g_{nu a}), we find that interactions change the flavor composition of neutrinos arriving on Earth for g_{nu a} > rsim 0.5,,mathrm{GeV}^{-1}, causing the electron(muon) flavor to dominate in the NO(IO) case for neutrino energies above sim 10^5,,mathrm{GeV}. Although current data on the flavor ratios suggest that interactions with UALP DM do not take place within the range of coupling studied (particularly in the NO case) more data is needed to improve the precision of the experimentally measured flavor composition.

Impact of Superconductors’ Properties on the Measurement Sensitivity of Resonant-Based Axion Detectors

Axions, hypothetical particles theorised to solve the strong CP problem, are presently being considered as strong candidates for cold dark matter constituents. The signal power of resonant-based axion detectors, known as haloscopes, is directly proportional to their quality factor Q. In this paper, the impact of the use of superconductors on the performances of haloscopes is studied by evaluating the obtainable Q. In particular, the surface resistance Rs of NbTi, Nb3Sn, YBa2Cu3O7−δ, and FeSe0.5Te0.5 is computed in the frequency, magnetic field, and temperature ranges of interest, starting from the measured vortex motion complex resistivity and the screening lengths of these materials. From Rs, the quality factor Q of a cylindrical haloscope with copper conical bases and a superconductive lateral wall, operating with the TM010 mode, is evaluated and used to perform a comparison of the performances of the different materials. Both YBa2Cu3O7−δ and FeSe0.5Te0.5 are shown to improve the measurement sensitivity by almost an order of magnitude, with respect to a whole Cu cavity, while NbTi is shown to be suitable only at lower frequencies (<10 GHz). Nb3Sn can provide an intermediate improvement of the whole spectrum of interest.

Ultralight axions versus primordial black holes

We reconsider entropy arguments which have been previously argued to support the idea that the dark matter constituents are primordial black holes with many solar masses. It has recently been shown that QCD axions which solve the strong CP problem may have masses [Formula: see text] in the extended range [Formula: see text]. Ultralight axions provide so many degrees of freedom that their entropy can exceed that of primordial black holes. This suggests that ultralight axions are more suited than primordial black holes to be constituents of dark matter.

Dark Matter Axions, Non-Newtonian Gravity and Constraints on Them from Recent Measurements of the Casimir Force in the Micrometer Separation Range

We consider axionlike particles as the most probable constituents of dark matter, the Yukawa-type corrections to Newton’s gravitational law and constraints on their parameters following from astrophysics and different laboratory experiments. After a brief discussion of the results by Prof. Yu. N. Gnedin in this field, we turn our attention to the recent experiment on measuring the differential Casimir force between Au-coated surfaces of a sphere and the top and bottom of rectangular trenches. In this experiment, the Casimir force was measured over an unusually wide separation region from 0.2 to 8μm and compared with the exact theory based on first principles of quantum electrodynamics at nonzero temperature. We use the measure of agreement between experiment and theory to obtain the constraints on the coupling constant of axionlike particles to nucleons and on the interaction strength of a Yukawa-type interaction. The constraints obtained on the axion-to-nucleon coupling constant and on the strength of a Yukawa interaction are stronger by factors of 4 and 24, respectively, than those found previously from gravitational experiments and measurements of the Casimir force but weaker than the constraints following from a differential measurement where the Casimir force was nullified. Some other already performed and planned experiments aimed at searching for axions and non-Newtonian gravity are discussed, and their prospects are evaluated.

Sterile Neutrinos as Dark Matter: Alternative Production Mechanisms in the Early Universe

We study various production mechanisms of sterile neutrinos in the early universe beyond and within the standard model. We obtain the quantum kinetic equations for production and the distribution function of sterile-like neutrinos at freeze-out, from which we obtain free streaming lengths, equations of state and coarse grained phase space densities. In a simple extension beyond the standard model, in which neutrinos are Yukawa coupled to a Higgs-like scalar, we derive and solve the quantum kinetic equation for sterile production and analyze the freeze-out conditions and clustering properties of this dark matter constituent. We argue that in the mass basis, standard model processes that produce active neutrinos also yield sterile-like neutrinos, leading to various possible production channels. Hence, the final distribution function of sterile-like neutrinos is a result of the various kinematically allowed production processes in the early universe. As an explicit example, we consider production of light sterile neutrinos from pion decay after the QCD phase transition, obtaining the quantum kinetic equation and the distribution function at freeze-out. A sterile-like neutrino with a mass in the keV range produced by this process is a suitable warm dark matter candidate with a free-streaming length of the order of few kpc consistent with cores in dwarf galaxies.

Primordial monopolium as dark matter

The existence of monopoles is a characteristic signature of Kaluza–Klein multidimensional theories. The topology of these solutions is extremely interesting. The existence of a dipole solution, which we have associated to a monopole–anti-monopole bound state, is the leitmotiv of this investigation. The dipole in its lowest energy state, which we here call also monopolium, is electromagnetically inert in free space interacting only gravitationally. Monopolium when interacting with time dependent magnetic fields acquires a time dependent induced magnetic moment and radiates. We have analyzed the most favorable astrophysical scenario for radiative monopolium and found that the amount of radiation is so small that is not detectable by conventional equipments. These findings suggest that Kaluza–Klein monopolium, if existent, would be a candidate for a primordial dark matter constituent.