Cold Particle Dark Matter

Possible dark matter candidates in particle physics span a mass range extending over fifty orders of magnitude. In this review, we consider the range of masses from a few keV to a few hundred TeV, which is relevant for cold particle dark matter. We will consider models where dark matter arises as weakly coupled elementary fields and models where dark matter is a composite state bound by a new strong interaction. Different production mechanisms for dark matter in these models will be described. The landscape of direct and indirect searches for dark matter and some of the resulting constraints on models will be briefly discussed.

Is non-particle dark matter equation of state parameter evolving with time?

Recently, the so-called Hubble Tension, i.e. the mismatch between the local and the cosmological measurements of the Hubble parameter, has been resolved when non-particle dark matter is considered which has a negative equation of state parameter ($$\omega \approx -\,0.01$$ ω ≈ - 0.01 ). We investigate if such a candidate can successfully describe the galactic flat rotation curves. It is found that the flat rotation curve feature puts a stringent constraint on the dark matter equation of state parameter $$\omega $$ ω and $$\omega \approx -\,0.01$$ ω ≈ - 0.01 is not consistent with flat rotational curves, observed around the galaxies. However, a dynamic $$\omega $$ ω of non-particle dark matter may overcome the Hubble tension without affecting the flat rotation curve feature.

Light dark matter scattering in gravitational wave detectors

We present prospects for discovering dark matter scattering in gravitational wave detectors. The focus of this work is on light, particle dark matter with masses below 1 $$\hbox {GeV}/\text {c}^{2}$$ GeV / c 2 . We investigate how a potential signal compares to typical backgrounds like thermal and quantum noise, first in a simple toy model and then using KAGRA as a realistic example. That shows that for a discovery much lighter and cooler mirrors would be needed. We also give some brief comments on space-based experiments and future atomic interferometers.

Addressing γ-ray emissions from dark matter annihilations in 45 Milky Way satellite galaxies and in extragalactic sources with particle dark matter models

ABSTRACT The mass-to-luminosity ratio of the dwarf satellite galaxies in the Milky Way suggests that these dwarf galaxies may contain substantial dark matter. The dark matter at the dense region such as within or at the vicinity of the centres of these dwarf galaxies may undergo the process of self-annihilation and produce γ-rays as the end product. The satellite borne γ-ray telescope such as Fermi-LAT reported the detection of γ-rays from around 45 Dwarf Spheroidals (dSphs) of Milky Way. In this work, we consider particle dark matter models described in the literature and after studying their phenomenologies, we calculate the γ-ray fluxes from the self-annihilation of the dark matter within the framework of these models in case of each of these 45 dSphs. We then compare the computed results with the observational upper bounds for γ-ray flux reported by Fermi-LAT and Dark Energy Survey for each of the 45 dSphs. The fluxes are calculated by adopting different dark matter density profiles. We then extend similar analysis for the observational upper bounds given by Fermi-LAT for the continuum γ-ray fluxes originating from extragalactic sources.

Sensitivity of the DARWIN observatory to the neutrinoless double beta decay of $$^{136}$$Xe

The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of $$^{136}$$ 136 Xe. Out of its 50 t total natural xenon inventory, 40 t will be the active target of a time projection chamber which thus contains about 3.6 t of $$^{136}$$ 136 Xe. Here, we show that its projected half-life sensitivity is $$2.4\times {10}^{27}\,{\hbox {year}}$$ 2.4 × 10 27 year , using a fiducial volume of 5 t of natural xenon and 10 year of operation with a background rate of less than 0.2 events/(t $$\cdot $$ · year) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in $$^{136}$$ 136 Xe.

The Milky Way’s rotation curve with superfluid dark matter

ABSTRACT Recent studies have shown that dark matter with a superfluid phase in which phonons mediate a long-distance force gives rise to the phenomenologically well-established regularities of Modified Newtonian Dynamics (mond). Superfluid dark matter, therefore, has emerged as a promising explanation for astrophysical observations by combining the benefits of both particle dark matter and mond, or its relativistic completions, respectively. We here investigate whether superfluid dark matter can reproduce the observed Milky Way rotation curve for $R \lt 25\, \rm {kpc}$ and are able to answer this question in the affirmative. Our analysis demonstrates that superfluid dark matter fits the data well with parameters in reasonable ranges. The most notable difference between superfluid dark matter and mond is that superfluid dark matter requires about $20{{\ \rm per\ cent}}$ less total baryonic mass (with a suitable interpolation function). The total baryonic mass is then $5.96 \times 10^{10}\, \mathrm{ M}_\odot$, of which $1.03 \times 10^{10}\, \mathrm{ M}_\odot$ are from the bulge, $3.95 \times 10^{10}\, \mathrm{ M}_\odot$ are from the stellar disc, and $0.98 \times 10^{10}\, \mathrm{ M}_\odot$ are from the gas disc. Our analysis further allows us to estimate the radius of the Milky Way’s superfluid core (concretely, the so-called nfw and thermal radii) and the total mass of dark matter in both the superfluid and the normal phase. By varying the boundary conditions of the superfluid to give virial masses $M_{200}^{\rm {DM}}$ in the range of $0.5\!-\!3.0 \times 10^{12}\, \mathrm{ M}_\odot$, we find that the Navarro, Frenk, and White (nfw) radius RNFW varies between $65$ and $73\, \rm {kpc}$, while the thermal radius RT varies between about $67$ and $105\, \rm {kpc}$. This is the first such treatment of a non-spherically symmetric system in superfluid dark matter.