61 research outputs found

    Fauna kopnenih jednakonožaca (Isopoda: Oniscidea) Baranje (Hrvatska)

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    Pitfall samples were taken during summer 2003 in 25 habitats of the Baranya triangle (Croatia) to describe the isopod fauna. The 125 traps caught a total of 2,808 isopods belonging to 11 species: Haplophthalmus danicus, Hyloniscus riparius, Platyarthrus hoffmannseggii, Cylisticus convexus, Porcellium collicola, Protracheoniscus politus, Trachelipus ratzeburgii, Trachelipus nodulosus, Trachelipus rathkii, Armadillidium vulgare and Armadillidium zenckeri. The most characteristic species of the area are A. vulgare, T. rathkii, P. collicola and H. riparius. The composition of the isopod assemblage proved to be similar to that in the Hungarian part of the Drava lowland.Tijekom ljeta 2003. godine na 25 postaja u hrvatskom dijelu Baranje uzorkovana je fauna kopnenih Isopoda metodom lovnih posuda. Uzorkovano je 2808 jednakonožaca uporabom 125 lovnih posuda. Uzorkovane jedinke svrstane su u 11 vrsta: Haplophthalmus danicus, Hyloniscus riparius, Platyarthrus hoffmannseggii, Cylisticus convexus, Porcellium collicola, Protracheoniscus politus, Trachelipus ratzeburgii, Trachelipus nodulosus, Trachelipus rathkii, Armadillidium vulgare i Armadillidium zenckeri. S obzirom na učestalost i lokalno rasprostranjenje za područje Baranje su najkarakterističnije vrste: A. vulgare, T. rathkii, P. collicola i H. riparius. Kvalitativni sastav faune jednakonožaca hrvatskog djela Baranje vrlo je sličan, te se poklapa s većinom vrsta faune jednakonožaca nizinskog područja Drave u Mađarskoj

    Prilog poznavanju faune ušara Hrvatske (Diptera: Hippoboscidae)

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    Faunistic research into louse flies (Hippoboscidae) in Croatia during the last two decades has increased the total number of louse flies known from this country to 11 species, of which Ornithoica turdi, Ornithophila metallica, Ornithomya avicularia, Ornithomya biloba, Ornithomya chloropus, Ornithomya fringillina, Crataerina melbae, Stenepteryx hirundinis and Icosta minor are new to Croatia.Faunistička istraživanja ušara (Hippoboscidae) tijekom posljednjih dvadeset godina u Hrvatskoj rezultirala su utvrđivanjem 11 vrsta, od kojih su drozdova ušara (Ornithoica turdi), sjajna ušara (Ornithophila metallica), velika ptičja ušara (Ornithomya avicularia), lastavičja ušara (Ornithomya biloba), tamna ptičja ušara (Ornithomya chloropus), mala ptičja ušara (Ornithomya fringillina), velika čiopina ušara (Crataerina melbae), piljkova ušara (Stenepteryx hirundinis) i mala čapljina ušara (Icosta minor) nove u fauni Hrvatske. Ukupni broj vrsta iz porodice ušara u Hrvatskoj fauni povećan je na 11 vrsta

    Search for solar axions using Li-7

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    We describe a novel approach to the search for solar, near-monochromatic hadronic axions, the latter being suggested to be created in the solar core during M1 transitions between the first excited level of Li-7, at 478 keV, and the ground state. As a result of Doppler broadening, in principle these axions can be detected via resonant absorption by the same nuclide on the Earth. Excited nuclei of Li-7 are produced in the solar interior by Be-7 electron capture and thus the axions are accompanied by emission of Be-7 solar neutrinos of energy 384 keV. An experiment was made which has yielded an upper limit on hadronic axion mass of 32 keV at the 95% confidence level.Comment: revtex, 4 pages with 2 figures, title revised, minor changes, matches version to appear in Phys. Rev.

    Recent searches for solar axions and large extra dimensions

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    We analyze the data from two recent experiments designed to search for solar axions within the context of multidimensional theories of the Kaluza-Klein type. In these experiments, axions were supposed to be emitted from the solar core, in M1 transitions between the first excited state and the ground state of 57Fe and 7Li. Because of the high multiplicity of axionic Kaluza-Klein states which couple with the strength of ordinary QCD axions, we obtain much more stringent experimental limits on the four-dimensional Peccei-Quinn breaking scale f_{PQ}, compared with the solar QCD axion limit. Specifically, for the 57Fe experiment, f_{PQ}>1x10^6 GeV in theories with two extra dimensions and a higher-dimensional gravitational scale M_H of order 100 TeV, and f_{PQ}>1x10^6 GeV in theories with three extra dimensions and M_H of order 1 TeV (to be compared with the QCD axion limit, f_{PQ}>8x10^3 GeV). For the 7Li experiment, f_{PQ}>1.4x10^5 GeV and 3.4x10^5 GeV, respectively (to be compared with the QCD axion limit, f_{PQ}>1.9x10^2 GeV). It is an interesting feature of our results that, in most cases, the obtained limit on f_{PQ} cannot be coupled with the mass of the axion, which is essentially set by the (common) radius of the extra dimensions.Comment: 4 pages, revtex 4, minor changes, version accepted by PR

    Prospects for the CERN Axion Solar Telescope Sensitivity to 14.4 keV Axions

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    The CERN Axion Solar Telescope (CAST) is searching for solar axions using the 9.0 T strong and 9.26 m long transverse magnetic field of a twin aperture LHC test magnet, where axions could be converted into X-rays via reverse Primakoff process. Here we explore the potential of CAST to search for 14.4 keV axions that could be emitted from the Sun in M1 nuclear transition between the first, thermally excited state, and the ground state of 57Fe nuclide. Calculations of the expected signals, with respect to the axion-photon coupling, axion-nucleon coupling and axion mass, are presented in comparison with the experimental sensitivity.Comment: 4 pages, 1 figure. Submitted to Nucl. Instr. and Meth.

    Results and perspectives of the solar axion search with the CAST experiment

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    The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of 3^3He as a buffer gas has allowed us to extend our sensitivity to higher axion masses than our previous measurements with 4^4He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eVma \le m_{a} \le 0.64 eV. From the absence of an excess of x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ2.3×1010_{a\gamma} \le 2.3\times 10^{-10} GeV1^{-1} at 95% C.L., the exact value depending on the pressure setting. CAST published results represent the best experimental limit on the photon couplings to axions and other similar exotic particles dubbed WISPs (Weakly Interacting Slim Particles) in the considered mass range and for the first time the limit enters the region favored by QCD axion models. Preliminary sensitivities for axion masses up to 1.16 eV will also be shown reaching mean upper limits on the axion-photon coupling of gaγ3.5×1010_{a\gamma} \le 3.5\times 10^{-10} GeV1^{-1} at 95% C.L. Expected sensibilities for the extension of the CAST program up to 2014 will be presented. Moreover long term options for a new helioscope experiment will be evoked.Comment: 4 pages, 2 pages, to appear in the proceedings of the 24th Rencontres de Blois V2 A few affiliations were not corrected in previous version V3 Author adde

    New solar axion search in CAST with 4^4He filling

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    The CERN Axion Solar Telescope (CAST) searches for aγa\to\gamma conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the X-ray refractive mass mγm_\gamma to the axion search mass mam_a. After the vacuum phase (2003--2004), which is optimal for ma0.02m_a\lesssim0.02 eV, we used 4^4He in 2005--2007 to cover the mass range of 0.02--0.39 eV and 3^3He in 2009--2011 to scan from 0.39--1.17 eV. After improving the detectors and shielding, we returned to 4^4He in 2012 to investigate a narrow mam_a range around 0.2 eV ("candidate setting" of our earlier search) and 0.39--0.42 eV, the upper axion mass range reachable with 4^4He, to "cross the axion line" for the KSVZ model. We have improved the limit on the axion-photon coupling to gaγ<1.47×1010GeV1g_{a\gamma}< 1.47\times10^{-10} {\rm GeV}^{-1} (95% C.L.), depending on the pressure settings. Since 2013, we have returned to vacuum and aim for a significant increase in sensitivity.Comment: CAST Collaboration 6 pages 3 figure

    Solar axion search with the CAST experiment

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    The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipe of an LHC dipole. The analysis of the data recorded during the first phase of the experiment with vacuum in the magnet pipes has resulted in the most restrictive experimental limit on the coupling constant of axions to photons. In the second phase, CAST is operating with a buffer gas inside the magnet pipes in order to extent the sensitivity of the experiment to higher axion masses. We will present the first results on the 4He^{4}{\rm He} data taking as well as the system upgrades that have been operated in the last year in order to adapt the experiment for the 3He^{3}{\rm He} data taking. Expected sensitivities on the coupling constant of axions to photons will be given for the recent 3He^{3}{\rm He} run just started in March 2008.Comment: Proceedings of the ICHEP 2008 conferenc

    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

    Search for low Energy solar Axions with CAST

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    We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.Comment: Paper submitted to the proceedings of the "4th Patras Workshop on Axions, WIMPs and WISPs", DESY, Hamburg Site - Germany, 18-21 June 2008. Author affiliations are reported on the title page of the paper. In version 2: 1 affiliation change, 3 references adde
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