2,196 research outputs found
Probing WIMPs in space-based gravitational wave experiments
Although searches for dark matter have lasted for decades, no convincing
signal has been found without ambiguity in underground detections, cosmic ray
observations, and collider experiments. We show by example that gravitational
wave (GW) observations can be a supplement to dark matter detections if the
production of dark matter follows a strong first-order cosmological phase
transition. We explore this possibility in a complex singlet extension of the
standard model with CP symmetry. We demonstrate three benchmarks in which the
GW signals from the first-order phase transition are loud enough for future
space-based GW observations, for example, BBO, U-DECIGO, LISA, Taiji, and
TianQin. While satisfying the constraints from the XENON1T experiment and the
Fermi-LAT gamma-ray observations, the dark matter candidate with its mass
around ~TeV in these scenarios has a correct relic abundance obtained
by the Planck observations of the cosmic microwave background radiation.Comment: 11 pages, 2 figures, 2 table
Updated constraints on Georgi-Machacek model, and its electroweak phase transition and associated gravitational waves
With theoretical constraints such as perturbative unitarity and vacuum
stability conditions and updated experimental data of Higgs measurements and
direct searches for exotic scalars at the LHC, we perform an updated scan of
the allowed parameter space of the Georgi-Machacek (GM) model. With the refined
global fit, we examine the allowed parameter space for inducing strong
first-order electroweak phase transitions (EWPTs) and find only the one-step
phase transition is phenomenologically viable. Based upon the result, we study
the associated gravitational wave (GW) signals and find most of which can be
detected by several proposed experiments. We also make predictions on processes
that may serve as promising probes to the GM model in the near future at the
LHC, including the di-Higgs productions and several exotic scalar production
channels.Comment: 42 pages, 11 figures, 9 table
Five-dimensional generalized gravity with curvature-matter coupling
The generalized gravity with curvature-matter coupling in
five-dimensional (5D) spacetime can be established by assuming a
hypersurface-orthogonal spacelike Killing vector field of 5D spacetime, and it
can be reduced to the 4D formulism of FRW universe. This theory is quite
general and can give the corresponding results to the Einstein gravity,
gravity with both no-coupling and non-minimal coupling in 5D spacetime as
special cases, that is, we would give the some new results besides previous
ones given by Ref.\cite{60}. Furthermore, in order to get some insight into the
effects of this theory on the 4D spacetime, by considering a specific type of
models with and , we not
only discuss the constraints on the model parameters , , but also
illustrate the evolutionary trajectories of the scale factor , the
deceleration parameter and the scalar field , in
the reduced 4D spacetime. The research results show that this type of
gravity models given by us could explain the current accelerated expansion of
our universe without introducing dark energy.Comment: arXiv admin note: text overlap with arXiv:0912.4581,
arXiv:gr-qc/0411066 by other author
- …