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.

Precise measurement of the W-boson mass with the CDF II detector

Abstract: We have measured the W-boson mass M{sub W} using data corresponding to 2.2 fb{sup -1} of integrated luminosity collected in p{bar p} collisions at {radical}s = 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470 126 W {yields} e{nu} candidates and 624 708 W {yields} {mu}{nu} candidates yield the measurement M{sub W} = 80 387 {+-} 12{sub stat} {+-} 15{sub syst} = 80 387 {+-} 19 MeV/c{sup 2}. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined.

The e+e-→2(π+π-)π0, 2(π+π-)η, K+K-π+π-π0 and K+K-π+π-η cross sections measured with initial-state radiation

Abstract: We study the processes $e^+ e^-\to 2(\pi^+\pi^-)\pi^0\gamma$, $2(\pi^+\pi^-)\eta\gamma$, $K^+ K^-\pi^+\pi^-\pi^0\gamma$ and $K^+ K^-\pi^+\pi^-\eta\gamma$ with the hard photon radiated from the initial state. About 20000, 4300, 5500 and 375 fully reconstructed events, respectively, are selected from 232 fb$^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective $e^+ e^-$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct \epem measurements, currently available only for the $\eta\pi^+\pi^-$ and $\omega\pi^+\pi^-$ submodes of the $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$ channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\to\omega(782)\pi^+\pi^-$ and study the $\omega(1420)$ and $\omega(1650)$ resonances. In the charmonium region, we observe the $J/\psi$ in all these final states and several intermediate states, as well as the $\psi(2S)$ in some modes, and we measure the corresponding branching fractions.

Search for a charged Higgs boson in pp collisions at s√=8 TeV

Abstract: A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 +/- 0.5 fb(-1) collected with the CMS detector in proton-proton collisions at root s = 8,TeV. The charged Higgs boson is searched for in top quark decays for m(H +/-) t(b)H-+/- for m(H +/-) > m(t) - m(b). The H-+/- -> tau(+/-)nu(tau) and H-+/- -> tb decay modes in the final states tau(h)+jets, mu tau(h), l+jets, and ll' (l =e, mu) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction B(t -> H(+/-)b) B(H-+/- -> tau(+/-)nu(tau)) = 1.2-0.15% is obtained in the mass range m(H +/-) = 80-160 GeV, while the upper limit on the cross section times branching fraction sigma(pp -> t(b)H-+/-) B(H-+/- -> tau(+/-)nu(tau)) = 0.38-0.025 pb is set in the mass range m(H)+ = 180-600 GeV. Here, sigma(pp -> t(b)H-+/-) stands for the cross section sum sigma(pp -> (t) over bar H+) + sigma(pp -> t (b) over bar H-). Assuming B(t -> H(+/-)b) = 1, an upper limit on sigma(pp -> t(b)H-+/-) of 2.0-0.13 pb is set for m(H +/-) = 180-600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m(H +/-)-tan beta parameter space in different MSSM benchmark scenarios.

Observation of electroweak production of same-sign W boson pairs in the two jet and two same-sign lepton final state in proton-proton collisions at s√= 13 TeV

Abstract: The first observation of electroweak production of same-sign W boson pairs in proton-proton collisions is reported The data sample corresponds to an integrated luminosity of 359 fb^(−1) collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC Events are selected by requiring exactly two leptons (electrons or muons) of the same charge, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass The observed significance of the signal is 55 standard deviations, where a significance of 57 standard deviations is expected based on the standard model The ratio of measured event yields to that expected from the standard model at leading order is 090 ± 022 A cross section measurement in a fiducial region is reported Bounds are given on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators and on the production of doubly charged Higgs bosons

Vehicle Stability Enhancement of Four-Wheel-Drive Hybrid Electric Vehicle Using Rear Motor Control

Abstract: A vehicle stability enhancement control algorithm for a four-wheel-drive hybrid electric vehicle (HEV) is proposed using rear motor driving, regenerative braking control, and electrohydraulic brake (EHB) control. A fuzzy-rule-based control algorithm is proposed, which generates the direct yaw moment to compensate for the errors of the sideslip angle and yaw rate. Performance of the vehicle stability control algorithm is evaluated using ADAMS and MATLAB Simulink cosimulations. HEV chassis elements such as the tires, suspension system, and steering system are modeled to describe the vehicle's dynamic behavior in more detail using ADAMS, whereas HEV power train elements such as the engine, motor, battery, and transmission are modeled using MATLAB Simulink with the control algorithm. It is found from the simulation results that the driving and regenerative braking at the rear motor is able to provide improved stability. In addition, better performance can be achieved by applying the driving and regenerative braking control, as well as EHB control.

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。