5,308 research outputs found

    A prototype for the AMS-RICH experiment

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    The AMS spectrometer will be installed on the International Space Station in 2005. Among other improvements over the first version of the instrument, a ring imaging Cherenkov detector (RICH) will be added and should open a new window for cosmic-ray physics, allowing isotope separation up to A = 25 between 1 and 10 GeV/c and element identification up to Z = 25 between threshold and 1 TeV/c/nucleon. It should also contribute to the high level of redundancy required for AMS and reject efficiency albedo particles. A second generation prototype has been operated for a few months : the architecture and the first results are presented.Comment: Proceedings of the 3rd International Conference on "New developments in photodetection" (Beaune - France

    Some aspects of primordial black hole physics

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    Small black holes should have formed in the early Universe if the density contrast was high enough. This article aims at giving a - biased and partial - short overview of the latest breakthroughs in this field. It first deals with tentative experimental detections thanks to gamma-rays and cosmic-rays. Primordial black holes (PBHs) are then considered as probes of the very small cosmological scales, far beyond any other classical observable. Finally, some possible "new physics" effects are considered, especially in the framework of higher dimensions.Comment: Proceedings of the International Conference on Theoretical Physics (TH2002), to appear in Annales Henri Poincar

    An improved gamma-ray limit on the density of PBHs

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    Gamma-rays are, with antiprotons, a very efficient way to derive upper limits on the density of evaporating black holes. They have been successfully used in the last decades to severely constrain the amount of Primordial Black Holes (PBHs) in our Universe. This article suggests a little refinement, based on the expected background, to improve this limit by a factor of three. The resulting value is : Omega_PBH < 3.3E-9.Comment: To appear in the 28th ICRC conference proceeding

    A RICH prototype for the AMS experiment

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    The AMS spectrometer will be installed on the International Space Station at the end of 2003. Among other improvements over the first version of the instrument, a ring imaging Cherenkov detector (RICH) will be added which latter should open a new window for cosmic-ray physics, allowing isotope separation up to A~25 between 1 and 10 GeV/c and elements identification up to Z~25 between threshold and 1 TeV/c/nucleon. It should also contribute to the high level of redundancy required for AMS and reject efficiency albedo particles. The results of the first generation prototype and the expected results of the new one are discussed.Comment: 4 pages, 6 figures, ICRC proceeding

    Peculiar Relics from Primordial Black Holes in the Inflationary Paradigm

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    Depending on various assumptions on the energy scale of inflation and assuming a primordial power spectrum of a Broken Scale Invariance (BSI) type, we explore the possibility for Primordial Black Holes (PBH) and Planck relics to contribute substantially to cold dark matter in the Universe. A recently proposed possibility to produce planck relics in 4-dimensional string gravity is considered. Possible experimental detection through gravitational waves is further explored. We stress that inflation with a low energy scale, and also possibly when Planck relics are produced, leads unavoidably to relics originating from PBHs that are not effectively classical during their formation, rendering the usual formalism inadequate for them.Comment: 10 pages; Results unchanged. Conclusion and reference adde

    Monte Carlo Production Management at CMS

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    The analysis of the LHC data at the Compact Muon Solenoid (CMS) experiment requires the production of a large number of simulated events. During the RunI of LHC (20102012), CMS has produced over 12 Billion simulated events, organized in approximately sixty different campaigns each emulating specific detector conditions and LHC running conditions (pile up). In order to aggregate the information needed for the configuration and prioritization of the events production, assure the book-keeping of all the processing requests placed by the physics analysis groups, and to interface with the CMS production infrastructure, the web- based service Monte Carlo Management (McM) has been developed and put in production in 2013. McM is based on recent server infrastructure technology (CherryPy + AngularJS) and relies on a CouchDB database back-end. This contribution covers the one and half year of operational experience managing samples of simulated events for CMS, the evolution of its functionalities and the extension of its capability to monitor the status and advancement of the events production

    Antiprotons from spallation of cosmic rays on interstellar matter

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    Cosmic ray antiprotons provide an important probe for the study of the galactic Dark Matter, as they could be produced by exotic sources. On the other hand, antiprotons are anyway produced by standard nuclear reactions of cosmic ray nuclei on interstellar matter. This process is responsible for a background flux that must be carefully determined to estimate the detectability of an hypothetical exotic signal. Estimates of this background suffer from potential uncertainties of various origins. The propagation of cosmic antiprotons depends on several physical characteristics of the Galaxy which are poorly known. Antiprotons are created from cosmic protons and helium nuclei whose fluxes were not measured with great accuracy until very recently. Calculations of antiproton fluxes make use of nuclear physics models with their own shortcomings and uncertainties. The goal of this paper is to give a new evaluation of the cosmic antiproton flux along with the associated uncertainties. The propagation parameters were tightly constrained in Maurin et al. 2001 by an analysis of cosmic ray nuclei data in the framework of a two-zone diffusion model and we apply these parameters to the propagation of antiprotons. We use the recently published data on proton and helion fluxes, and we find that this particular source of uncertainty has become negligible. The Monte Carlo program DTUNUC was used to carefully examine nuclear reactions. We find that all the cosmic antiproton fluxes naturally coming out of the calculation are fully compatible with experimental data. Uncertainties in this flux have been strongly reduced. Those related to propagation are less than 25%. All other possible sources of uncertainty have also been studied

    Black Hole Relics in String Gravity: Last Stages of Hawking Evaporation

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    One of the most intriguing problem of modern physics is the question of the endpoint of black hole evaporation. Based on Einstein-dilaton-Gauss-Bonnet four dimensional string gravity model we show that black holes do not disappear and that the end of the evaporation process leaves some relic. The possibility of experimental detection of the remnant black holes is investigated. If they really exist, such objects could be a considerable part of the non baryonic dark matter in our Universe.Comment: 15 pages, accepted to Class. Quant. Gra

    Atmospheric and Galactic Production and Propagation of Light Antimatter Nuclei

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    The production and propagation of light antimatter nuclei has been calculated using inclusive antiproton production cross sections from a new data analysis, and coalescence models for the production of composite particles. Particles were propagated using recently proven phenomenological approaches. The atmospheric secondary flux is evaluated for the first time. The Galactic flux obtained are larger than those obtained previously in similar calculations. The non-annihilating scattering contributions of the propagated particles are introduced. The preliminary results are shown and discussed.Comment: 4 pages, Contribution to the ICRC 200

    The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

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    A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200
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