120 research outputs found

    Search for axions in streaming dark matter

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    A new search strategy for the detection of the elusive dark matter (DM) axion is proposed. The idea is based on streaming DM axions, whose flux might get temporally enormously enhanced due to gravitational lensing. This can happen if the Sun or some planet (including the Moon) is found along the direction of a DM stream propagating towards the Earth location. The experimental requirements to the axion haloscope are a wide-band performance combined with a fast axion rest mass scanning mode, which are feasible. Once both conditions have been implemented in a haloscope, the axion search can continue parasitically almost as before. Interestingly, some new DM axion detectors are operating wide-band by default. In order not to miss the actually unpredictable timing of a potential short duration signal, a network of co-ordinated axion antennae is required, preferentially distributed world-wide. The reasoning presented here for the axions applies to some degree also to any other DM candidates like the WIMPs.Comment: 5 page

    Potential for measurement of the tensor electric and magnetic polarizabilities of the deuteron in storage-ring experiments with polarized beams

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    Measurement of the tensor electric and magnetic polarizabilities of the deuteron is of great interest, especially in connection with the possibilities of COSY and GSI. These polarizabilities can be measured in storage rings by the frozen spin method providing a disappearance of g-2 precession. This method will be used in the planned deuteron electric-dipole-moment experiment in storage rings. The tensor electric polarizability of the deuteron significantly influences the buildup of the vertical polarization in the above experiment. The spin interactions depending on the electric dipole moment, the tensor electric polarizability, and main systematical errors caused by field misalignments have very different symmetries. For the considered experimental conditions, the sensitivity to the deuteron EDM of 1×1029e1\times10^{-29} e\cdotcm corresponds to measuring the both of tensor polarizabilities with an accuracy of δαTδβT5×1042\delta\alpha_T\approx\delta\beta_T\approx5\times10^{-42} cm3^3. This conservative estimate can be improved by excluding the systematical error caused by the field instability which is negligible for the measurement of the tensor polarizabilities. To find the tensor magnetic polarizability, the horizontal components of the polarization vector should be measured.Comment: 11 pages, the extended version of the paper prepared for the Proceedings of 19th International Spin Physics Symposium (September 27 - October 2, 2010, Julich, Germany

    HNBR and its MWCNT reinforced nanocomposites : Crystalline morphology and electrical response

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    Morphology and electrical response of hydrogenated acrylonitrile butadiene rubber (HNBR) and its multiwall carbon nanotube (MWCNT) reinforced nanocomposites were studied by means of x-ray diffraction and broadband dielectric spectroscopy. HNBR systems were found to be semi-crystalline, with their crystallinity to increase with the addition of MWCNTs. In their dielectric spectra, four relaxation processes were detected. Ascending in relaxation time, these were attributed to: (i) interfacial polarization at the interface of crystalline and amorphous regions of HNBR and at the interface between HNBR and MWCNTs, (ii) glass to rubber transition of the amorphous part of HNBR, (iii) rearrangement of polar side groups, such as –CN, and (iv) local motions of small segments of the main elastomer chain. Electrical conductivity increases with MWCNT content and frequency increasing. The effect of temperature, on the electrical response, is more pronounced at low frequencies. The temperature dependence of the electrical conductivity strongly deviates from a pure Arrhenius behavior, signifying that the occurring conductance mechanisms do not correspond to a single thermally activated process. Relaxation dynamics imply that crystalline regions exert motion restrictions to large segments of the macromolecules in the amorphous phase and to polar parts of the systems

    aKWISP: investigating short-distance interactions at sub-micron scales

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    The sub-micron range in the field of short distance interactions has yet to be opened to experimental investigation, and may well hold the key to understanding al least part of the dark matter puzzle. The aKWISP (advanced-KWISP) project introduces the novel Double Membrane Interaction Monitor (DMIM), a combined source-sensing device where interaction distances can be as short as 100 nm or even 10 nm, much below the 1-10 micron distance which is the lower limit encountered by current experimental efforts. aKWISP builds on the technology and the results obtained with the KWISP opto-mechanical force sensor now searching at CAST for the direct coupling to matter of solar chameleons. It will reach the ultimate quantum-limited sensitivity by exploiting an array of technologies, including operation at milli-Kelvin temperatures. Recent suggestions point at short-distance interactions studies as intriguing possibilities for the detection of axions and of new physical phenomena

    Atmospheric Temperature anomalies as manifestation of the dark Universe

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    We are investigating the possible origin of small-scale anomalies, like the annual stratospheric temperature anomalies. Unexpectedly within known physics, their observed planetary "dependency", does not match concurrent solar activity, whose impact on the atmosphere is unequivocal; this points at an additional energy source of exo-solar origin. A viable concept behind such observations is based on possible gravitational focusing by the Sun and its planets towards the Earth of low-speed invisible streaming matter; its influx towards the Earth gets temporally enhanced. Only a somehow "strongly" interacting invisible streaming matter with the small upper atmospheric screening can be behind the observed temperature excursions. Ordinary dark matter (DM) candidates like axions or WIMPs, cannot have any noticeable impact. The associated energy deposition is O(1000GeV/cm2/sec)\mathcal{O}(\sim 1000\, \mathrm{GeV}/{{\mathrm{cm}}^2}/\mathrm{sec}). The atmosphere has been uninterruptedly monitored for decades. Therefore, the upper atmosphere can serve as a novel (low-threshold) detector for the dark Universe, with built-in spatiotemporal resolution while the solar system gravity acts temporally as a signal amplifier. Interestingly, the anomalous ionosphere shows a relationship with the inner earth activity like earthquakes. Similarly investigating the transient sudden stratospheric warmings within the same reasoning, the nature of the assumed "invisible streams" could be deciphered.Comment: 8 pages, 7 figures, Published in the proceedings of the "15th International Conference on Meteorology, Climatology and Atmospheric Physics (COMECAP 2021)" see https://www.conferre.gr/allevents/comecap2020/Proceedings_Final.pd

    Search for chameleons with CAST

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    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter (βm\beta_{\rm m}) and to photons (βγ\beta_{\gamma}) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1\,keV to 400\,eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600\,eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of βγ ⁣ ⁣1011\beta_{\gamma}\!\lesssim\!10^{11} for 1<βm<1061<\beta_{\rm m}<10^6.Comment: 8 pages, 12 figure

    Axion Searches with Helioscopes and astrophysical signatures for axion(-like) particles

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    The first part reviews the working mechanisms, capabilities and performance of axion helioscopes, including the achieved results so far. The 2nd part is observationally driven. New simulation results obtained with the Geant4 code reconstruct spectral shape of solar X-ray spectra, and their isotropic emission and lateral size. The derived rst mass of the axion(-like) particles is ~10meV. The axion interaction with magnetic field gradient is a generic theoretical suggestion that could reconcile present limits with relevant solar X-ray activity. A short outlook of the experimentally expanding solar axion field is given.Comment: 31 pages, 18 figures. Aded 1 author, updated references. Accepted for the special issue of NJP on dark matter (July 2009
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