13 research outputs found
Daily modulation and gravitational focusing in direct dark matter search experiments
We study the effect of gravitational focusing of the earth on dark matter. We
find that the effect can produce a detectable diurnal modulation in the dark
matter signal for part of the parameter space which for high dark matter masses
is larger than the diurnal modulation induced by the fluctuations in the flux
of dark matter particles due to the rotation of the earth around its own axis.
The two sources of diurnal modulation have different phases and can be
distinguished from each other. We demonstrate that the diurnal modulation can
potentially check the self-consistency of experiments that observe annual
modulated signals that can be attributed to dark matter. Failing to discover a
daily varying signal can result conclusively to the falsification of the
hypothesis that the annual modulation is due to dark matter. We also suggest
that null result experiments should check for a daily modulation of their
rejected background signal with specific phases. A potential discovery could
mean that dark matter collisions have been vetoed out.Comment: 8 pages, 4 figures (published version
The Sun as a sub-GeV Dark Matter Accelerator
Sub-GeV halo dark matter that enters the Sun can potentially scatter off hot
solar nuclei and be ejected much faster than its incoming velocity. We derive
an expression for the rate and velocity distribution of these reflected
particles taking into account the Sun's temperature and opacity. We further
demonstrate that future direct detection experiments could use these energetic
reflected particles to probe light dark matter in parameter space that cannot
be accessed via ordinary halo dark matter.Comment: 5 pages, 2 figures, v2: matches the published versio
Inflation from Asymptotically Safe Theories
We investigate models in which inflation is driven by an ultraviolet safe and
interacting scalar sector stemming from a new class of nonsupersymmetric gauge
field theories. These new theories, differently from generic scalar models, are
well defined to arbitrary short distances because of the existence of a
controllable ultraviolet interacting fixed point. The scalar couplings at the
ultraviolet fixed point and their overall running are predicted by the
geometric structure of the underlying theory. We analyse the minimal and
non-minimal coupling to gravity of these theories and the consequences for
inflation. In the minimal coupling case the theory requires large
non-perturbative quantum corrections to the quantum potential for the theory to
agree with data, while in the non- minimal coupling case the perturbative
regime in the couplings of the theory is preferred. Requiring the theory to
reproduce the observed amplitude of density perturbations constrain the
geometric data of the theory such as the number of colors and flavors for
generic values of the non-minimal coupling.Comment: 6 pages, 6 figure
Boson Stars from Self-Interacting Dark Matter
We study the possibility that self-interacting bosonic dark matter forms
star-like objects. We study both the case of attractive and repulsive
self-interactions, and we focus particularly in the parameter phase space where
self-interactions can solve well standing problems of the collisionless dark
matter paradigm. We find the mass radius relations for these dark matter
bosonic stars, their density profile as well as the maximum mass they can
support.Comment: 12 pages, 6 figures; references adde
Neutron Star Stability in Light of the Neutron Decay Anomaly.
A recent proposal suggests that experimental discrepancies on the lifetime of neutrons can be resolved if neutrons decay to dark matter. At the same time it has been demonstrated that such a decay mode would soften the nuclear equation of the state resulting in neutron stars with a maximum mass much below currently observed ones. In this Letter, we demonstrate that appropriate dark matter-baryon interactions can accommodate neutron stars with mass above two solar masses. We compare this stabilization mechanism to one based on dark matter self-interactions, finding that it is less sensitive to the details of the nuclear equation of state. We present a simple microscopic model realization of this mechanism