12,403 research outputs found

    A map of the non-thermal WIMP

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    We study the effect of the elastic scattering on the non-thermal WIMP, which is produced by direct decay of heavy particles at the end of reheating. The non-thermal WIMP becomes important when the reheating temperature is well below the freeze-out temperature. Usually, two limiting cases have been considered. One is that the produced high energetic dark matter particles are quickly thermalized due to the elastic scattering with background radiations. The corresponding relic abundance is determined by the thermally averaged annihilation cross-section at the reheating temperature. The other one is that the initial abundance is too small for the dark matter to annihilate so that the final relic is determined by the initial amount itself. We study the regions between these two limits, and show that the relic density depends not only on the annihilation rate, but also on the elastic scattering rate. Especially, the relic abundance of the p-wave annihilating dark matter crucially relies on the elastic scattering rate because the annihilation cross-section is sensitive to the dark matter velocity. We categorize the parameter space into several regions where each region has distinctive mechanism for determining the relic abundance of the dark matter at the present Universe. The consequence on the (in)direct detection is also studied.Comment: 9 pages, 5 figures; v2: discussion improved, matches version published in PL

    Monomial Relization of Crystal Bases for Special Linear Lie Algebras

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    We give a new realization of crystal bases for finite dimensional irreducible modules over special linear Lie algebras using the monomials introduced by H. Nakajima. We also discuss the connection between this monomial realization and the tableau realization given by Kashiwara and Nakashima.Comment: 15 page

    New fitting formula for cosmic non-linear density distribution

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    We have measured the probability distribution function (PDF) of cosmic matter density field from a suite of N-body simulations. We propose the generalized normal distribution of version 2 (Nv2) as an alternative fitting formula to the well-known log-normal distribution. We find that Nv2 provides significantly better fit than the log-normal distribution for all smoothing radii (2, 5, 10, 25 [Mpc/h]) that we studied. The improvement is substantial in the underdense regions. The development of non- Gaissianities in the cosmic matter density field is captured by continuous evolution of the skewness and shifts parameters of the Nv2 distribution. We present the redshift evolution of these parameters for aforementioned smoothing radii and various background cosmology models. All the PDFs measured from large and high-resolution N-body simulations that we use in this study can be obtained from a Web site at https://astro.kias.re.kr/jhshin.Comment: Accepted for publication in Ap

    Young Wall Realization of Crystal Bases for Classical Lie Algebras

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    In this paper, we give a new realization of crystal bases for finite dimensional irreducible modules over classical Lie algebras. The basis vectors are parameterized by certain Young walls lying between highest weight and lowest weight vectors.Comment: 27page

    Trends in Scale and Structure of Korea's Health Expenditure over Last Three Decades (1980-2009): Financing, Functions and Providers

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    This paper introduces statistics related to the size and composition of Korea's total health expenditure. The figures produced were tailored to the OECD's system of health accounts. Korea's total health expenditure in 2009 was estimated at 73.7 trillion won (US57.7billion).TheannualpercapitahealthexpenditurewasequivalenttoUS 57.7 billion). The annual per capita health expenditure was equivalent to US PPP 1,879. Korea's total health expenditure as a share of gross domestic product was 6.9% in 2009, far below the OECD average of 9.5%. Korea's public financing share of total health expenditure increased rapidly from less than 50% before 2000 to 58.2% in 2009. However, despite this growth, Korea's share remained the fourth lowest among OECD countries that had an average public share of 71.5%. Inpatient, outpatient, and pharmaceutical care accounted for 32.1%, 33.0%, and 23.7% of current health expenditure in 2009, respectively. A total of 41.1% of current health expenditure went to hospitals, 28.1% to providers of ambulatory healthcare (15.9% on doctor's clinics), and 17.9% to pharmacies. More investment in the translation of national health account data into policy-relevant information is suggested for future progress
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