4,173 research outputs found
Cosmological Probes for Supersymmetry
The multi-parameter character of supersymmetric dark-matter models implies
the combination of their experimental studies with astrophysical and
cosmological probes. The physics of the early Universe provides nontrivial
effects of non-equilibrium particles and primordial cosmological structures.
Primordial black holes (PBHs) are a profound signature of such structures that
may arise as a cosmological consequence of supersymmetric (SUSY) models.
SUSY-based mechanisms of baryosynthesis can lead to the possibility of
antimatter domains in a baryon asymmetric Universe. In the context of
cosmoparticle physics, which studies the fundamental relationship of the micro-
and macro-worlds, the development of SUSY illustrates the main principles of
this approach, as the physical basis of the modern cosmology provides
cross-disciplinary tests in physical and astronomical studies.Comment: Invited review to the special issue "Supersymmetry and Dark matter"
(ed. D.Cline) of the Symmetry journal. arXiv admin note: substantial text
overlap with arXiv:0801.0116, arXiv:1311.246
Testing Split Supersymmetry with Inflation
Split supersymmetry (SUSY) -- in which SUSY is relevant to our universe but
largely inaccessible at current accelerators -- has become increasingly
plausible given the absence of new physics at the LHC, the success of gauge
coupling unification, and the observed Higgs mass. Indirect probes of split
SUSY such as electric dipole moments (EDMs) and flavor violation offer hope for
further evidence but are ultimately limited in their reach. Inflation offers an
alternate window into SUSY through the direct production of superpartners
during inflation. These particles are capable of leaving imprints in future
cosmological probes of primordial non-gaussianity. Given the recent
observations of BICEP2, the scale of inflation is likely high enough to probe
the full range of split SUSY scenarios and therefore offers a unique advantage
over low energy probes. The key observable for future experiments is
equilateral non-gaussianity, which will be probed by both cosmic microwave
background (CMB) and large scale structure (LSS) surveys. In the event of a
detection, we forecast our ability to find evidence for superpartners through
the scaling behavior in the squeezed limit of the bispectrum.Comment: 19 pages, 6 figure
Dark Matter in the Coming Decade: Complementary Paths to Discovery and Beyond
In this report we summarize the many dark matter searches currently being
pursued through four complementary approaches: direct detection, indirect
detection, collider experiments, and astrophysical probes. The essential
features of broad classes of experiments are described, each with their own
strengths and weaknesses. The complementarity of the different dark matter
searches is discussed qualitatively and illustrated quantitatively in two
simple theoretical frameworks. Our primary conclusion is that the diversity of
possible dark matter candidates requires a balanced program drawing from all
four approaches.Comment: Report prepared for the Community Summer Study (Snowmass) 2013, on
behalf of Cosmic Frontier Working Groups 1-4 (CF1: WIMP Dark Matter Direct
Detection, CF2: WIMP Dark Matter Indirect Detection, CF3: Non-WIMP Dark
Matter, and CF4: Dark Matter Complementarity); published versio
Dark Matter and LHC: What is the Connection?
We review what can (and cannot) be learned if dark matter is detected in one
or more experiments, emphasizing the importance of combining LHC data with
direct, astrophysical and cosmological probes of dark matter. We briefly review
the conventional picture of a thermally produced WIMP relic density and its
connection with theories of electroweak symmetry breaking. We then discuss both
experimental and theoretical reasons why one might generically expect this
picture to fail. If this is the case, we argue that a combined effort bringing
together all types of data -- combined with explicitly constructed theoretical
models -- will be the only way to achieve a complete understanding of the dark
matter in our universe and become confident that any candidate actually
provides the relic density.Comment: 25 pages, 2 figures, Invited review for Modern Physics Letters
The Spacetime Superalgebras in a Massive IIA Background via Brane Probes
We derive the spacetime superalgebras explicitly from ``test'' p-brane
actions in a D-8-brane (i.e. a massive IIA) background to the lowest order in
via canonical formalism, and show that the forms of the superalgebras
are the same as those in all the other D-brane (i.e. massless IIA) backgrounds,
that is, they are indifferent to the presence of the Chern-Simons terms which
are proportional to the mass and added to the D-brane actions in the case of
massive IIA backgrounds. Thus, we can say that all the D-brane background
solutions including a D-8-brane are on equal footing from the viewpoint of the
superalgebras via brane probes. We also deduce from the algebra all the
previously known 1/4 supersymmetric intersections of a p-brane or a fundamental
string with a D-8-brane, as the supersymmetric ``gauge fixings'' of the test
branes in the D-8-brane background.Comment: 15pages, Latex, in v2 two references added and some grammatical and
spelling errors corrected. in v3 the title is a bit modified and one
reference is adde
Supersymmteric Null-like Holographic Cosmologies
We construct a new class of 1/4-BPS time dependent domain-wall solutions with
null-like metric and dilaton in type II supergravities, which admit a null-like
big bang singularity. Based on the domain-wall/QFT correspondence, these
solutions are dual to 1/4-supersymmetric quantum field theories living on a
boundary cosmological background with time dependent coupling constant and UV
cutoff. In particular we evaluate the holographic function for the
2-dimensional dual field theory living on the corresponding null-like
cosmology. We find that this function runs in accordance with the
-theorem as the boundary universe evolves, this means that the number of
degrees of freedom is divergent at big bang and suggests the possible
resolution of big bang singularity.Comment: 26 pages;v2 references adde
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