Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSearch for composite dark matter with optically levitated sensors
77
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Results are reported from a search for a class of composite dark matter models with feeble, long-range interactions with normal matter. We search for impulses arising from passing dark matter particles by monitoring the mechanical motion of an optically levitated nanogram mass over the course of several days. Assuming such particles constitute the dominant component of dark matter, this search places upper limits on their interaction with neutrons of $alpha_n leq 1.2 times 10^{-7}$ at 95% confidence for dark matter masses between 1--10 TeV and mediator masses $m_phi leq 0.1$ eV. Due to the large enhancement of the cross-section for dark matter to coherently scatter from a nanogram mass ($sim 10^{29}$ times that for a single neutron) and the ability to detect momentum transfers as small as $sim$200 MeV/c, these results provide sensitivity to certain classes of composite dark matter models that substantially exceeds existing searches, including those employing kg-scale or ton-scale targets. Extensions of these techniques can enable directionally-sensitive searches for a broad class of previously inaccessible heavy dark matter candidates.
rate research
Read More
We propose a tunable resonant sensor to detect gravitational waves in the frequency range of 50-300 kHz using optically trapped and cooled dielectric microspheres or micro-discs. The technique we describe can exceed the sensitivity of laser-based gravitational wave observatories in this frequency range, using an instrument of only a few percent of their size. Such a device extends the search volume for gravitational wave sources above 100 kHz by 1 to 3 orders of magnitude, and could detect monochromatic gravitational radiation from the annihilation of QCD axions in the cloud they form around stellar mass black holes within our galaxy due to the superradiance effect.
We investigate a new method to search for keV-scale sterile neutrinos that could account for Dark Matter. Neutrinos trapped in our galaxy could be captured on stable $^{163}$Dy if their mass is greater than 2.83 keV. Two experimental realizations are studied, an integral counting of $^{163}$Ho atoms in dysprosium-rich ores and a real-time measurement of the emerging electron spectrum in a dysprosium-based detector. The capture rates are compared to the solar neutrino and radioactive backgrounds. An integral counting experiment using several kilograms of $^{163}$Dy could reach a sensitivity for the sterile-to-active mixing angle $sin^2theta_{e4}$ of $10^{-5}$ significantly exceeding current laboratory limits. Mixing angles as low as $sin^2theta_{e4} sim 10^{-7}$ / $rm m_{^{163}rm Dy}rm{(ton)}$ could possibly be explored with a real-time experiment.
This Letter reports results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 $mu$eV. The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at sub-kelvin temperatures, thereby reducing thermal noise as well as the excess noise from the ultra-low-noise SQUID amplifier used for the signal power readout. Ongoing searches will provide nearly definitive tests of the invisible axion model over a wide range of axion masses.
The understanding of the origin of dark matter has great importance for cosmology and particle physics. Several interesting extensions of the standard model dealing with solution of this problem motivate the concept of hidden sectors consisting of SU(3)xSU(2)_LxU(1)_Y singlet fields. Among these models, the mirror matter model is certainly one of the most interesting. The model explains the origin of parity violation in weak interactions, it could also explain the baryon asymmetry of the Universe and provide a natural ground for the explanation of dark matter. The mirror matter could have a portal to our world through photon-mirror photon mixing (epsilon). This mixing would lead to orthopositronium (o-Ps) to mirror orthopositronium oscillations, the experimental signature of which is the apparently invisible decay of o-Ps. In this paper, we describe an experiment to search for the decay o-Ps -> invisible in vacuum by using a pulsed slow positron beam and a massive 4pi BGO crystal calorimeter. The developed high efficiency positron tagging system, the low calorimeter energy threshold and high hermiticity allow the expected sensitivity in mixing strength to be epsilon about 10^-9, which is more than one order of magnitude below the current Big Bang Nucleosynthesis limit and in a region of parameter space of great theoretical and phenomenological interest. The vacuum experiment with such sensitivity is particularly timely in light of the recent DAMA/LIBRA observations of the annual modulation signal consistent with a mirror type dark matter interpretation.
Numbers of tabletop experiments have made efforts to detect large extra dimensions for the range from solar system to submillimeter system, but the direct evidence is still lacking. Here we present a scheme to test the gravitational law in 4+2 dimensions at microns by using cavity optomechanical method. We have investigated the probe spectrum for coupled quantum levitated oscillators in optical cavities. The results show that the spectral splitting can be obtained once the large extra dimensions present. Compare to the previous experiment, the sensitivity can be improved by the using of a specific geometry and a shield mirror to control and suppress the effect of the Casimir background. The weak frequency splitting can be optically read by the pump-probe scheme. Thus we can detect the gravitational deviation in the bulk based ADD model via spectroscopy without the isoelectronic technique.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
