scholarly journals Constraining the non-gravitational scattering of baryons and dark matter with early cosmic structure formation

2019 ◽  
Vol 487 (4) ◽  
pp. 4711-4720 ◽  
Author(s):  
Boyuan Liu ◽  
Anna T P Schauer ◽  
Volker Bromm
Keyword(s):  
Dark Matter ◽  
Structure Formation ◽  
Particle Physics ◽  
Small Scale ◽  
Interaction Cross Section ◽  
Number Density ◽  
Absorption Signal ◽  
Measured Absorption ◽  
Sigma 1 ◽  
Dark Matter Scattering

ABSTRACT We derive new constraints on the non-gravitational baryon-dark matter scattering (BDMS) by evaluating the mass thresholds of dark matter (DM) haloes in which primordial gas can cool efficiently to form Population III (Pop III) stars, based on the timing of the observed 21 cm absorption signal. We focus on the BDMS model with interaction cross-section $\sigma =\sigma _{1}[v/(1\ \mathrm{km\, s^{-1}})]^{-4}$, where v is the relative velocity of the encounter. Our results rule out the region in parameter space with $\sigma _{1}\gtrsim 10^{-19}\, \mathrm{cm^{2}}$ and DM particle mass mχc2 ≲ 3 × 10−2 GeV, where the cosmic number density of Pop III hosts at redshift z ∼ 20 is at least three orders of magnitude smaller than in the standard Lambda cold DM (ΛCDM) case. In these BDMS models, the formation of Pop III stars is significantly suppressed for z ≳ 20, inconsistent with the timing of the observed global 21 cm absorption signal. For the fiducial BDMS model with mχc2 = 0.3 GeV and $\sigma _{1}=8\times 10^{-20}\, \mathrm{cm^{2}}$, capable of accommodating the measured absorption depth, the number density of Pop III hosts is reduced by a factor of 3−10 at z ∼ 15−20, when the 21 cm signal is imprinted, compared with the ΛCDM model. The confluence of future detailed cosmological simulations with improved 21 cm observations promises to probe the particle-physics nature of DM at the small-scale frontier of early structure formation.

scholarly journals Hidden sector monopole dark matter with matter domination

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Michael L. Graesser ◽  
Jacek K. Osiński
Keyword(s):  
Dark Matter ◽  
Cross Sections ◽  
Particle Physics ◽  
Magnetic Monopoles ◽  
Number Density ◽  
Pure Radiation ◽  
Hidden Sector ◽  
Equilibrium Dynamics ◽  
Thermal Histories ◽  
Relic Abundance

Abstract The thermal freeze-out mechanism for relic dark matter heavier than O(10 − 100 TeV) requires cross-sections that violate perturbative unitarity. Yet the existence of dark matter heavier than these scales is certainly plausible from a particle physics perspective, pointing to the need for a non-thermal cosmological history for such theories. Topological dark matter is a well-motivated scenario of this kind. Here the hidden-sector dark matter can be produced in abundance through the Kibble-Zurek mechanism describing the non-equilibrium dynamics of defects produced in a second order phase transition. We revisit the original topological dark matter scenario, focusing on hidden-sector magnetic monopoles, and consider more general cosmological histories. We find that a monopole mass of order (1–105) PeV is generic for the thermal histories considered here, if monopoles are to entirely reproduce the current abundance of dark matter. In particular, in a scenario involving an early era of matter domination, the monopole number density is always less than or equal to that in a pure radiation dominated equivalent provided a certain condition on critical exponents is satisfied. This results in a larger monopole mass needed to account for a fixed relic abundance in such cosmologies.

scholarly journals Small-scale Substructure in Dark Matter Haloes: Where Does Galaxy Formation Come to an End?

2004 ◽  
Vol 220 ◽  
pp. 91-98 ◽  
Author(s):  
J. E. Taylor ◽  
J. Silk ◽  
A. Babul
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Structure Formation ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Small Scale ◽  
Analytic Model ◽  
Model Predictions ◽  
Low Mass

Models of structure formation based on cold dark matter predict that most of the small dark matter haloes that first formed at high redshift would have merged into larger systems by the present epoch. Substructure in present-day haloes preserves the remains of these ancient systems, providing the only direct information we may ever have about the low-mass end of the power spectrum. We describe some recent attempts to model halo substructure down to very small masses, using a semi-analytic model of halo formation. We make a preliminary comparison between the model predictions, observations of substructure in lensed systems, and the properties of local satellite galaxies.

scholarly journals Voronoi volume function: a new probe of cosmology and galaxy evolution

2020 ◽  
Vol 495 (3) ◽  
pp. 3233-3251 ◽  
Author(s):  
Aseem Paranjape ◽  
Shadab Alam
Keyword(s):  
Dark Matter ◽  
Galaxy Evolution ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Voronoi Tessellation ◽  
Small Scale ◽  
Summary Statistics ◽  
Number Density ◽  
Volume Function ◽  
Space Effects

ABSTRACT We study the Voronoi volume function (VVF) – the distribution of cell volumes (or inverse local number density) in the Voronoi tessellation of any set of cosmological tracers (galaxies/haloes). We show that the shape of the VVF of biased tracers responds sensitively to physical properties such as halo mass, large-scale environment, substructure, and redshift-space effects, making this a hitherto unexplored probe of both primordial cosmology and galaxy evolution. Using convenient summary statistics – the width, median, and a low percentile of the VVF as functions of average tracer number density – we explore these effects for tracer populations in a suite of N-body simulations of a range of dark matter models. Our summary statistics sensitively probe primordial features such as small-scale oscillations in the initial matter power spectrum (as arise in models involving collisional effects in the dark sector), while being largely insensitive to a truncation of initial power (as in warm dark matter models). For vanilla cold dark matter (CDM) cosmologies, the summary statistics display strong evolution and redshift-space effects, and are also sensitive to cosmological parameter values for realistic tracer samples. Comparing the VVF of galaxies in the Galaxies & Mass Assembly (GAMA) survey with that of abundance-matched CDM (sub)haloes tentatively reveals environmental effects in GAMA beyond halo mass (modulo unmodelled satellite properties). Our exploratory analysis thus paves the way for using the VVF as a new probe of galaxy evolution physics as well as the nature of dark matter and dark energy.

scholarly journals The halo mass function in alternative dark matter models

2020 ◽  
Vol 493 (1) ◽  
pp. L11-L15 ◽  
Author(s):  
M R Lovell
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Particle Physics ◽  
Mass Function ◽  
Small Scale ◽  
Acoustic Oscillations ◽  
Sterile Neutrinos ◽  
Matter Power Spectrum ◽  
Alternative Approach ◽  
Good Agreement

ABSTRACT The claimed detection of large amounts of substructure in lensing flux anomalies, and in Milky Way stellar stream gap statistics, has led to a step change in constraints on simple warm dark matter models. In this study, we compute predictions for the halo mass function both for these simple models and for comprehensive particle physics models of sterile neutrinos and dark acoustic oscillations. We show that the mass function fit of Lovell et al. underestimates the number of haloes less massive than the half-mode mass, $M_\mathrm {hm}$, by a factor of 2, relative to the extended Press–Schechter (EPS) method. The alternative approach of applying EPS to the Viel et al. matter power spectrum fit instead suggests good agreement at $M_\mathrm {hm}$ relative to the comprehensive model matter power spectrum results, although the number of haloes with mass $\rm{\lt} M_\mathrm {hm}$ is still suppressed due to the absence of small-scale power in the fitting function. Overall, we find that the number of dark matter haloes with masses $\rm{\lt} 10^{8}{\, \rm M_\odot }$ predicted by competitive particle physics models is underestimated by a factor of ∼2 when applying popular fitting functions, although careful studies that follow the stripping and destruction of subhaloes will be required in order to draw robust conclusions.

scholarly journals Continuum-mediated self-interacting dark matter

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Ian Chaffey ◽  
Sylvain Fichet ◽  
Philip Tanedo
Keyword(s):  
Dark Matter ◽  
Yukawa Potential ◽  
Spatial Separation ◽  
Small Scale ◽  
Interaction Cross Section ◽  
De Sitter ◽  
Strongly Coupled ◽  
Integer Power ◽  
Low Mass ◽  
Sommerfeld Enhancement

Abstract Dark matter may self-interact through a continuum of low-mass states. This happens if dark matter couples to a strongly-coupled nearly-conformal hidden sector. This type of theory is holographically described by brane-localized dark matter interacting with bulk fields in a slice of 5D anti-de Sitter space. The long-range potential in this scenario depends on a non-integer power of the spatial separation, in contrast to the Yukawa potential generated by the exchange of a single 4D mediator. The resulting self-interaction cross section scales like a non-integer power of velocity. We identify the Born, classical and resonant regimes and investigate them using state-of-the-art numerical methods. We demonstrate the viability of our continuum-mediated framework to address the astrophysical small-scale structure anomalies. Investigating the continuum-mediated Sommerfeld enhancement, we demonstrate that a pattern of resonances can occur depending on the non-integer power. We conclude that continuum mediators introduce novel power-law scalings which open new possibilities for dark matter self-interaction phenomenology.

scholarly journals To Observe, or Not to Observe, Quantum-Coherent Dark Matter in the Milky Way, That is a Question

2021 ◽  
Vol 8 ◽  
Author(s):  
Tanja Rindler-Daller
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Structure Formation ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Small Scale ◽  
Quantum Mechanical ◽  
Bose Einstein ◽  
The Impact ◽  
Observational Signature

In recent years, Bose-Einstein-condensed dark matter (BEC-DM) has become a popular alternative to standard, collisionless cold dark matter (CDM). This BEC-DM -also called scalar field dark matter (SFDM)- can suppress structure formation and thereby resolve the small-scale crisis of CDM for a range of boson masses. However, these same boson masses also entail implications for BEC-DM substructure within galaxies, especially within our own Milky Way. Observational signature effects of BEC-DM substructure depend upon its unique quantum-mechanical features and have the potential to reveal its presence. Ongoing efforts to determine the dark matter substructure in our Milky Way will continue and expand considerably over the next years. In this contribution, we will discuss some of the existing constraints and potentially new ones with respect to the impact of BEC-DM onto baryonic tracers. Studying dark matter substructure in our Milky Way will soon resolve the question, whether dark matter behaves classical or quantum on scales of ≲ 1 kpc.

scholarly journals Study of rare nuclear processes with CUORE

2018 ◽  
Vol 33 (09) ◽  
pp. 1843002 ◽  
Author(s):  
C. Alduino ◽  
K. Alfonso ◽  
F. T. Avignone ◽  
O. Azzolini ◽  
G. Bari ◽  
...  
Keyword(s):  
Dark Matter ◽  
Electron Capture ◽  
Beta Decay ◽  
Upper Bound ◽  
Half Life ◽  
Particle Physics ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Small Scale ◽  
Nuclear Processes

TeO2 bolometers have been used for many years to search for neutrinoless double beta decay in [Formula: see text]Te. CUORE, a tonne-scale TeO2 detector array, recently published the most sensitive limit on the half-life, [Formula: see text] yr, which corresponds to an upper bound of 140–400 meV on the effective Majorana mass of the neutrino. While it makes CUORE a world-leading experiment looking for neutrinoless double beta decay, it is not the only study that CUORE will contribute to in the field of nuclear and particle physics. As already done over the years with many small-scale experiments, CUORE will investigate both rare decays (such as the two-neutrino double beta decay of [Formula: see text]Te and the hypothesized electron capture in [Formula: see text]Te), and rare processes (e.g. dark matter and axion interactions). This paper describes some of the achievements of past experiments that used TeO2 bolometers, and perspectives for CUORE.

scholarly journals A Cosmologist's Tour through the New Particle Zoo (Candy Shop?)

1987 ◽  
Vol 117 ◽  
pp. 445-488
Author(s):  
Michael S. Turner
Keyword(s):  
Dark Matter ◽  
Structure Formation ◽  
Particle Physics ◽  
Elementary Particle Physics ◽  
Recent Developments ◽  
History Of ◽  
Density Inhomogeneities ◽  
Invisible Axion ◽  
Birth Processes ◽  
The Universe

Recent developments in elementary particle physics have led to a renaissance in cosmology, in general, and in the study of structure formation, in particular. Already, the study of the very early (t ≤ 10−2 sec) history of the Universe has provided valuable hints as to the ‘initial data’ for the structure formation problem — the nature and origin of the primeval density inhomogeneities, the quantity and composition of matter in the Universe today, and numerous candidates for the constituents of the ubiquitious dark matter. I review the multitude of WIMP candidates for the dark matter provided by modern particle physics theories, putting them into context by briefly discussing the theories which predict them. I also review their various birth sites and birth processes in the early Universe. At present the most promising candidates seem to be a 30 or so eV neutrino, a few GeV photino, or the ‘invisible axion’ (weighing in at about 10−5 eV!), with a planck mass monopole, quark nuggets, and shadow matter as the leading ‘dark’ horse candidates. I also mention some very exotic possibilities — unstable WIMPs, cosmic strings, and even the possibility of a relic cosmological term.

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