12,403 research outputs found
A map of the non-thermal WIMP
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
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
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
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
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 (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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