Hyun-Chul Kim

Bio: Hyun-Chul Kim is an academic researcher from Inha University. The author has contributed to research in topics: Large Hadron Collider & Lepton. The author has an hindex of 176, co-authored 4076 publications receiving 183227 citations. Previous affiliations of Hyun-Chul Kim include Konkuk University & University of Edinburgh.

Measurements of the angular distributions in the decays B→K(*)μ(+)μ(-) at CDF.

Abstract: We reconstruct the decays B → K(*) µ+µ- and measure their angular distributions in pp collisions at √s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 6.8 fb-1. The transverse polarization asymmetry AT(2) and the time-reversal-odd charge-and-parity asymmetry Aim are measured for the first time, together with the K* longitudinal polarization fraction FL and the µ on forward-backward asymmetry AFB, for the decays B0→K*0µ+µ- and B0→K*+µ+µ-. Our results are among the most accurate to date and consistent with those from other experiments.

Missing transverse energy performance of the CMS detector

Abstract: During 2010 the LHC delivered pp collisions with a centre-of-mass energy of 7 TeV. In this paper, the results of comprehensive studies of missing transverse energy as measured by the CMS detector are presented. The results cover the measurements of the scale and resolution for missing transverse energy, and the effects of multiple pp interactions within the same bunch crossings on the scale and resolution. Anomalous measurements of missing transverse energy are studied, and algorithms for their identification are described. The performances of several reconstruction algorithms for calculating missing transverse energy are compared. An algorithm, called missing-transverse-energy significance, which estimates the compatibility of the reconstructed missing transverse energy with zero, is described, and its performance is demonstrated.

Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at sqrt(s) = 8 TeV

Abstract: A search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of multijet events corresponding to an integrated luminosity of 19.7 inverse femtobarns, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. The search uses novel jet-substructure identification techniques that provide sensitivity to the presence of highly boosted vector bosons decaying into a pair of quarks. Exclusion limits are set at a confidence level of 95% on the production of: (i) excited quark resonances q* decaying to qW and qZ for masses less than 3.2 TeV and 2.9 TeV, respectively, (ii) a Randall-Sundrum graviton G[RS] decaying into WW for masses below 1.2 TeV, and (iii) a heavy partner of the W boson W' decaying into WZ for masses less than 1.7 TeV. For the first time mass limits are set on W' to WZ and G[RS] to WW in the all-jets final state. The mass limits on q* to qW, q* to qZ, W' to WZ, G[RS] to WW are the most stringent to date. A model with a "bulk" graviton G[Bulk] that decays into WW or ZZ bosons is also studied.

Evidence for neutrino oscillations from muon decay at rest.

Abstract: A search for \ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathrm{\ensuremath{\mu}}}$\ensuremath{\rightarrow}\ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{e}}$ oscillations has been conducted at the Los Alamos Meson Physics Facility using \ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathrm{\ensuremath{\mu}}}$ from ${\mathrm{\ensuremath{\mu}}}^{+}$ decay at rest. The \ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{e}}$ are detected via the reaction \ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{ep}}$\ensuremath{\rightarrow}${\mathit{e}}^{+}$n, correlated with the 2.2 MeV \ensuremath{\gamma} from np\ensuremath{\rightarrow}d\ensuremath{\gamma}. The use of tight cuts to identify ${\mathit{e}}^{+}$ events with correlated \ensuremath{\gamma} rays yields 22 events with ${\mathit{e}}^{+}$ energy between 36 and 60 MeV and only 4.6\ifmmode\pm\else\textpm\fi{}0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$. A ${\mathrm{\ensuremath{\chi}}}^{2}$ fit to the entire ${\mathit{e}}^{+}$ sample results in a total excess of 51.${0}_{\mathrm{\ensuremath{-}}19.5}^{+20.2}$\ifmmode\pm\else\textpm\fi{}8.0 events with ${\mathit{e}}^{+}$ energy between 20 and 60 MeV. If attributed to \ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathrm{\ensuremath{\mu}}}$\ensuremath{\rightarrow}\ensuremath{ u}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{e}}$ oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.05)%. \textcopyright{} 1996 The American Physical Society.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。