278 research outputs found

    Multiple Dp_p-branes as a Dp+2_{p+2}-brane

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    From BFSS matrix theory considerations, it is expected that a single Dp+2_{p+2}-brane action can be obtained from N Dp_p-brane action in large N limit. We examine and confirm this expectation by working out the details of DBI and Chern-Simons terms of Dp+2_{p+2}-brane action from Dp_{p}-brane action. We show that the same relation works for non-BPS, as well as BPS branesComment: 14 page

    Spectrum of Background X-rays from Moduli Dark Matter

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    We examine the XX-ray spectrum from the decay of the dark-matter moduli with mass ∌O(100)\sim {\cal O}(100)keV, in particular, paying attention to the line spectrum from the moduli trapped in the halo of our galaxy. It is found that with the energy resolution of the current experiments (∌10\sim 10%) the line intensity is about twice stronger than that of the continuum spectrum from the moduli that spread in the whole universe. Therefore, in the future experiments with higher energy resolutions it may be possible to detect such line photons. We also investigate the Îł\gamma-ray spectrum emitted from the decay of the multi-GeV moduli. It is shown that the emitted photons may form MeV-bump in the Îł\gamma-ray spectrum. We also find that if the modulus mass is of the order of 10 GeV, the emitted photons at the peak of the continuum spectrum loses their energy by the scattering and the shape of the spectrum is significantly changed, which makes the constraint weaker than that obtained in the previous works.Comment: 14 pages (RevTeX file) including four postscript figures, reviced version to be published in Physical Review

    Cosmological Moduli Problem in Gauge-mediated Supersymmetry Breaking Theories

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    A generic class of string theories predicts the existence of light moduli fields, and they are expected to have masses mϕm_\phi comparable to the gravitino mass m3/2m_{3/2} which is in a range of 10−210^{-2}keV--1GeV in gauge-mediated supersymmetry breaking theories. Such light fields with weak interactions suppressed by the Planck scale can not avoid some stringent cosmological constraints, that is, they suffer from `cosmological moduli problems'. We show that all the gravitino mass region 10−210^{-2}keV â‰Čm3/2â‰Č\lesssim m_{3/2} \lesssim 1GeV is excluded by the constraints even if we incorporate a late-time mini-inflation (thermal inflation). However, a modification of the original thermal inflation model enables the region 10−210^{-2}keV â‰Čm3/2â‰Č\lesssim m_{3/2} \lesssim 500keV to survive the constraints. It is also stressed that the moduli can be dark matter in our universe for the mass region 10−210^{-2}keV â‰Čmϕâ‰Č\lesssim m_\phi \lesssim 100keV.Comment: A few changes in section IV and

    Native Birdlife in Hawke’s Bay: application of the river values assessment system (RiVAS and RiVAS+)

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    This report presents an application of the River Values Assessment System for existing value (RiVAS) and for potential value (RiVAS+) to native birdlife in the Hawkes Bay Region. A workshop was held in Napier on 3rd October 2011 to apply the method. This Hawkes Bay Region bird report needs to be read in conjunction with the method and with the first native bird application reports (see Hughey et al. 2010 and Gaze et al. 2010).Ministry of Science and Information, and Hawkes Bay Regional Counci

    On the Moduli Problem and Baryogenesis in Gauge-mediated SUSY Breaking Models

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    We investigate whether the Affleck-Dine mechanism can produce sufficient baryon number of the universe in the gauge-mediated SUSY breaking models, while evading the cosmological moduli problem by late-time entropy production. We find that the Q-ball formation renders the scenario very difficult to work, irrespective of the detail mechanism of the entropy production.Comment: 11 pages, RevTeX, 5 postscript figures include

    Efficient upconversion of sub-THz radiation in a high-Q whispering gallery resonator

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    We demonstrate efficient upconversion of sub-THz radiation into the optical domain in a high-Q whispering gallery mode resonator with quadratic optical nonlinearity. The 5x10^{-3} power conversion efficiency of continuous wave 100GHz signal is achieved with only 16 mW of optical pump.Comment: This revision is limited to discussion of only optical WGMs coupled with the external Rf field. Discussion of RF WGMs is now posted separatel
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