84 research outputs found

    Status of Evidence for Neutrinoless Double Beta Decay

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    The present experimental status in the search for neutrinoless double beta decay is reviewed, with emphasis on the first indication for neutrinoless double beta decay found in the Heidelberg-Moscow experiment, giving first evidence for lepton number violation and a Majorana nature of the neutrinos. Future perspectives of the field are briefly outlined.Comment: 37 pages, latex, 23 figures, Published in Found. Phys. 32 (2002) 1181-1223 and Presented at Fourth Heidelberg International Conference on Dark Matter in Astro- and Particle Physics, DARK2002, Cape Town, South Africa, 4 - 9 February, 2002, eds. H.V. Klapdor-Kleingrothaus and R. Viollier, Springer-Verlag Heidelberg, (2002) 367-403 see Home Page of Heidelberg Non-Accelerator Particle Physics Group: http://www.mpi-hd.mpg.de/non_acc/buecher.html#DARK200

    Search for neutrinoless double beta decay with enriched 76Ge in Gran Sasso 1990-2003

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    The results of the HEIDELBERG-MOSCOW experiment which searches with 11 kg of enriched 76Ge for double beta decay in the GRAN Sasso underground laboratory are presented for the full running period August 1990 - May 2003. The duty cycle of the experiment was ~80%, the collected statistics is 71.7 kg y. The background achieved in the energy region of the Q value for double beta decay is 0.11 events/ kg y keV. The two-neutrino accompanied half-life is determined on the basis of more than 100 000 events. The confidence level for the neutrinoless signal has been improved to 4.2 sigma.Comment: 19 pages, latex, 9 figures, 2 table

    First Results from the HDMS experiment in the Final Setup

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    The Heidelberg Dark Matter Search (HDMS) is an experiment designed for the search for WIMP dark matter. It is using a special configuration of Ge detectors, to efficiently reduce the background in the low-energy region below 100 keV. After one year of running the HDMS detector prototype in the Gran Sasso Underground Laboratory, the inner crystal of the detector has been replaced with a HPGe crystal of enriched 73^{73}Ge. The final setup started data taking in Gran Sasso in August 2000. The performance and the first results of the measurement with the final setup are discussed.Comment: 8 pages, revtex, 7 figures, Home Page of Heidelberg Non-Accelerator Particle Physics Group: http://www.mpi-hd.mpg.de/non_acc

    Evidence for Neutrinoless Double Beta Decay

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    The data of the Heidelberg-Moscow double beta decay experiment for the measuring period August 1990 - May 2000 (54.9813 kg y or 723.44 molyears), published recently, are analyzed using the potential of the Bayesian method for low counting rates. First evidence for neutrinoless double beta decay is observed giving first evidence for lepton number violation. The evidence for this decay mode is 97% (2.2\sigma) with the Bayesian method, and 99.8% c.l. (3.1\sigma) with the method recommended by the Particle Data Group. The half-life of the process is found with the Bayesian method to be T_{1/2}^{0\nu} = (0.8 - 18.3) x 10^{25} y (95% c.l.) with a best value of 1.5 x 10^{25} y. The deduced value of the effective neutrino mass is, with the nuclear matrix elements from [Sta90,Tom91] = (0.11 - 0.56) eV (95% c.l.), with a best value of 0.39 eV. Uncertainties in the nuclear matrix elements may widen the range given for the effective neutrino mass by at most a factor 2. Our observation which at the same time means evidence that the neutrino is a Majorana particle, will be of fundamental importance for neutrino physics. PACS. 14.69.Pq Neutrino mass and mixing; 23.40.Bw Weak-interaction and lepton (including neutrino) aspects 23.40.-s Beta decay; double beta decay; electron and muon capture.Comment: 14 pages, psfile, 7 figures, Published in Modern Physics Letters A, Vol. 16, No. 37 (2001) 2409-2420, World Scientific Publishing Company, Home Page: http://ejournals.wspc.com.sg/mpla/16/1637/S0217732301005825.html, Home Page of Heidelberg Non-Accelerator Particle Physics Group: http://www.mpi-hd.mpg.de/non_acc

    Modern etiological and pathogenetic aspects of chronic peripheral uveitis

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    Intermediate uveitis is among most severe forms of endogenous uveitis which is more common in young people, being characterized by minimal clinical manifestations at early stages of the disorder. A significant and, sometimes, irreversible decrease in visual acuity is associated with development of long-term complications of chronic cintermediate uveitis (CIU), i.e., complicating cataracts (in up to 57% of the cases), cystic maular edema developing at a frequency of up to 31%), as well as ophthalmic hypertension and glaucoma (up to 16% of the patients). The incidence rate of CIU is 1.5 per 100,000 per year. The eye, despite its high immune privilege, is susceptible to infectious and inflammatory diseases. Clinical and histopathological data suggest autoimmune origin of CIU associated with possible response to some endogenous antigen of unknown origin. The main effectors of inflammation in peripheral chorioretinal structures are CD4+T lymphocytes, which are found in paravasal infiltrates and vitreoretinal exudates in CIU. An important role in CIU pathogenesis is attributed to IL-6 and IL-8, TNFá, vascular endothelial growth factor (VEGF), and micro-RNAs, which show increased expression in most CIU patients. Impaired state of intestinal bacterial microbiome is a potential trigger of intraocular inflammation. Genetic predisposition for CIU was also revealed, due to polymorphisms of human leukocyte antigens and some other genes. It is necessary to expand and deepen our knowledge on the disease pathogenesis, in order to develop effective pharmacological treatment of CIU. The article is review of literature discussing the modern scientific ideas concerning etiology and mechanisms of the CIU development

    Advanced Laboratory Methods for Detecting Yellow Fever Pathogen

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    Yellow fever is an acute infectious disease of viral nature, the causative agent of which is vector-borne –is transmitted through the bites of infected mosquitoes. Massive epidemics caused by the yellow fever virus are observed in the countries of Africa, South and Central America annually. Imported cases are also registered in non-endemic territories. The review presents the currently available data on the distribution, structure and classification of the yellow fever virus, the identification of its genetic variants depending on the geographical distribution, as well as modern methods of detection and identification of the pathogen in samples taken from sick and dead people. It considers the possibility of using virological, immunoserological and molecular-genetic methods for the diagnosis of yellow fever in different periods from the onset of the disease and in retrospective studies. The lists of diagnostic drugs of domestic and foreign production for the detection of agent markers (antigen, RNA), as well as specific antibodies of IgM and IgG classes, approved for use on the territory of the Russian Federation, are provided. The relevance of further development, improvement and introduction into laboratory practice of reagent kits that allow to detect the yellow fever virus in samples from sick people in a short time, with high efficiency and specificity is demonstrated. This will help to establish a diagnosis promptly and conduct timely anti-epidemic measures, as well as to determine the level of the population stratum immune to the pathogen in endemic regions and evaluate the effectiveness of immunization for the vaccinated contingent

    New Data on the Dissemination of the Nipah Virus (<i>Henipavirus. Paramyxoviridae</i>) and Methods of its Indication and Identification

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    Nipah virus (Nipah virus, NiV) is a representative of the genus Henipavirus of the Paramyxoviridae family, the causative agent of a dangerous infectious disease with a wide range of clinical manifestations – from an asymptomatic (subclinical) form to severe encephalitis with fatal outcome. Despite the fact that the disease caused by this virus is registered only in the countries of Southeast Asia, the possibility of importing the pathogen to non-endemic territories is not excluded. Also, this pathogen is able to infect not only a large number of people, but also animals, causing serious diseases and significant economic damage, posing both, a medical and veterinary problem. This review presents the data available in the modern press on the structure and classification of the Nipah virus, possible cycles of its transmission, spread, methods of indication and identification in clinical and biological material, as well as the effectiveness of their use depending on the timing of the onset of the disease and available commercial diagnostic and preventive drugs

    Search for Cold Dark Matter and Solar Neutrinos with GENIUS and GENIUS-TF

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    The new project GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Further it has the potential to be a real-time detector for low-energy (pp and 7Be) solar neutrinos. A GENIUS Test Facility has just been funded and will come into operation by end of 2002.Comment: 4 pages, revtex, 3 figures, Talk was presented at International School on Nuclear Physics, 23rd Course: Neutrinos in Astro, Particle and Nuclear Physics, Erice, September 18 - 26, 2001, Publ. in Progress in Particle and Nuclear Physics, Vol. 48 (2002) 283 - 286, Home Page of Heidelberg Non-Accelerator Particle Physics Group: http://www.mpi-hd.mpg.de/non_acc
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