700,784 research outputs found

### Theory of Dark Matter

We discuss the hypothesis that the constituents of dark matter in the
galactic halo are Primordial Intermediate-Mass Black Holes (PIMBHs). The status
of axions and WIMPs is discussed, as are the methods for detecting PIMBHs with
emphasis on microlensing. The role of the angular momentum J of the PIMBHs in
their escaping previous detection is considered.Comment: 17 pages LaTeX. Talk at Conference on Cosmology, Gravitational Waves
and Particles. Nanyang Technological University, Singapore. February 6-10,
2017. arXiv admin note: text overlap with arXiv:1510.00400, arXiv:1608.0500

### M-theory dark matter

The phenomenological implications of the eleven dimensional limit of
$M$-theory (strongly coupled $E_8\times E_8$) are investigated. In particular
we calculate the supersymmetric particle spectrum subject to constraints of
correct electroweak symmetry breaking and the requirement that the lightest
supersymmetric particle provides the dark matter of the universe. We also
calculate direct detection event rates of the lightest neutralino relevant for
non-baryonic dark matter experiments. The modulation effect, due to Earth's
annual motion is also calculated.Comment: LaTeX file, 30 pages including 12 figures;v2 typos fixed and
references adde

### Theory of Dark Matter

The search for dark matter is a very wide and active field of research. Many
potential hints of dark matter have appeared recently which led to a burst of
theoretical activity and model building. I necessarily concentrate here only in
some aspects of it. I review here some recent hints and some of the ways in
which they could be explained.Comment: Plenary review talk at "Physics at the LHC 2010", 7-12 June 2010,
DESY, Hamburg, Germany; 6 pages, no figures, desyproc.cls file needed to
typese

### Wave Dark Matter and the Tully-Fisher Relation

We investigate a theory of dark matter called wave dark matter, also known as
scalar field dark matter (SFDM) and boson star dark matter or Bose-Einstein
condensate (BEC) dark matter, in spherical symmetry and its relation to the
Tully-Fisher relation. We show that fixing the oscillation frequency of wave
dark matter near the edge of dark galactic halos implies a Tully-Fisher-like
relation for those halos. We then describe how this boundary condition, which
is roughly equivalent to fixing the half-length of the exponentially decaying
tail of each galactic halo mass profile, may yield testable predictions for
this theory of dark matter.Comment: 19 pages, 4 figure

### Prospects for direct detection of dark matter in an effective theory approach

We perform the first comprehensive analysis of the prospects for direct
detection of dark matter with future ton-scale detectors in the general
11-dimensional effective theory of isoscalar dark matter-nucleon interactions
mediated by a heavy spin-1 or spin-0 particle. The theory includes 8 momentum
and velocity dependent dark matter-nucleon interaction operators, besides the
familiar spin-independent and spin-dependent operators. From a variegated
sample of 27 benchmark points selected in the parameter space of the theory, we
simulate independent sets of synthetic data for ton-scale Germanium and Xenon
detectors. From the synthetic data, we then extract the marginal posterior
probability density functions and the profile likelihoods of the model
parameters. The associated Bayesian credible regions and frequentist confidence
intervals allow us to assess the prospects for direct detection of dark matter
at the 27 benchmark points. First, we analyze the data assuming the knowledge
of the correct dark matter nucleon-interaction type, as it is commonly done for
the familiar spin-independent and spin-dependent interactions. Then, we analyze
the simulations extracting the dark matter-nucleon interaction type from the
data directly, in contrast to standard analyses. This second approach requires
an extensive exploration of the full 11-dimensional parameter space of the dark
matter-nucleon effective theory. Interestingly, we identify 5 scenarios where
the dark matter mass and the dark matter-nucleon interaction type can be
reconstructed from the data simultaneously. We stress the importance of
extracting the dark matter nucleon-interaction type from the data directly,
discussing the main challenges found addressing this complex 11-dimensional
problem.Comment: 23 pages, 7 figures, replaced to match the published versio

### Dark galactic halos without dark matter

Using standard Einstein theory, baryonic mass cannot account for observed
galactic rotation velocities and gravitational lensing, attributed to galactic
dark matter halos. In contrast, theory constrained by Weyl conformal scaling
symmetry explains observed galactic rotation in the halo region without
invoking dark matter. An explanation of dark halos, gravitational lensing, and
structural stabilization, without dark matter and consistent with conformal
theory, is proposed here. Condensation of uniform primordial matter into a
material cloud or galaxy vacates a large surrounding spherical halo. Within
such an extended vacancy in the original cosmic background mass-energy density,
conformal theory predicts centripetal acceleration of the observed magnitude.Comment: 5 pages, updated text, recent references added, accepted for
Europhysics Letter

### ETHOS - An Effective Theory of Structure Formation: From dark particle physics to the matter distribution of the Universe

We formulate an effective theory of structure formation (ETHOS) that enables
cosmological structure formation to be computed in almost any microphysical
model of dark matter physics. This framework maps the detailed microphysical
theories of particle dark matter interactions into the physical effective
parameters that shape the linear matter power spectrum and the self-interaction
transfer cross section of non-relativistic dark matter. These are the input to
structure formation simulations, which follow the evolution of the cosmological
and galactic dark matter distributions. Models with similar effective
parameters in ETHOS but with different dark particle physics would nevertheless
result in similar dark matter distributions. We present a general method to map
an ultraviolet complete or effective field theory of low energy dark matter
physics into parameters that affect the linear matter power spectrum and carry
out this mapping for several representative particle models. We further propose
a simple but useful choice for characterizing the dark matter self-interaction
transfer cross section that parametrizes self-scattering in structure formation
simulations. Taken together, these effective parameters in ETHOS allow the
classification of dark matter theories according to their structure formation
properties rather than their intrinsic particle properties, paving the way for
future simulations to span the space of viable dark matter physics relevant for
structure formation.Comment: 16 pages + Appendix, 4 figures. Published in Phys. Rev. D. This paper
is part of a series of papers on constructing an effective theory of
structure formation (ETHOS) that maps almost any microphysical model of dark
matter physics to effective parameters for cosmological structure formation.
v3: Matches accepted version. v4: Updated definition of dark radiation
perturbation variable

### Dark Nuclei I: Cosmology and Indirect Detection

In a companion paper (to be presented), lattice field theory methods are used
to show that in two-color, two-flavor QCD there are stable nuclear states in
the spectrum. As a commonly studied theory of composite dark matter, this
motivates the consideration of possible nuclear physics in this and other
composite dark sectors. In this work, early Universe cosmology and indirect
detection signatures are explored for both symmetric and asymmetric dark
matter, highlighting the unique features that arise from considerations of dark
nuclei and associated dark nuclear processes. The present day dark matter
abundance may be composed of dark nucleons and/or dark nuclei, where the latter
are generated through it dark nucleosynthesis. For symmetric dark matter,
indirect detection signatures are possible from annihilation, dark
nucleosynthesis, and dark nuclear capture and we present a novel explanation of
the galactic center gamma ray excess based on the latter. For asymmetric dark
matter, dark nucleosynthesis may alter the capture of dark matter in stars,
allowing for captured particles to be processed into nuclei and ejected from
the star through dark nucleosynthesis in the core. Notably, dark
nucleosynthesis realizes a novel mechanism for indirect detection signals of
asymmetric dark matter from regions such as the galactic center, without having
to rely on a symmetric dark matter component.Comment: 31 pages, 9 figure

### On the way from matter-dominated era to dark energy universe

We develop the general program of the unification of matter-dominated era
with acceleration epoch for scalar-tensor theory or dark fluid. The general
reconstruction of single scalar-tensor theory is fulfilled. The explicit form
of scalar potential for which the theory admits matter-dominated era,
transition to acceleration and (asymptotically deSitter) acceleration epoch
consistent with WMAP data is found. The interrelation of the epochs of
deceleration-acceleration transition and matter dominance-dark energy
transition for dark fluids with general EOS is investigated. We give several
examples of such models with explicit EOS (using redshift parametrization)
where matter-dark energy domination transition may precede the
deceleration-acceleration transition. As some by-product, the reconstruction
scheme is applied to scalar-tensor theory to define the scalar potentials which
may produce the dark matter effect. The obtained modification of Newton
potential may explain the rotation curves of galaxies.Comment: LaTeX 12 pages, 1 figure, extended version to appear in PR

### Non-relativistic effective theory of dark matter direct detection

Dark matter direct detection searches for signals coming from dark matter
scattering against nuclei at a very low recoil energy scale ~ 10 keV. In this
paper, a simple non-relativistic effective theory is constructed to describe
interactions between dark matter and nuclei without referring to any underlying
high energy models. It contains the minimal set of operators that will be
tested by direct detection. The effective theory approach highlights the set of
distinguishable recoil spectra that could arise from different theoretical
models. If dark matter is discovered in the near future in direct detection
experiments, a measurement of the shape of the recoil spectrum will provide
valuable information on the underlying dynamics. We bound the coefficients of
the operators in our non-relativistic effective theory by the null results of
current dark matter direct detection experiments. We also discuss the mapping
between the non-relativistic effective theory and field theory models or
operators, including aspects of the matching of quark and gluon operators to
nuclear form factors.Comment: 35 pages, 3 figures, Appendix C.3 revised, acknowledgments and
references adde

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