Wolfgang Wagner

Bio: Wolfgang Wagner is an academic researcher from Vienna University of Technology. The author has contributed to research in topics: Large Hadron Collider & Top quark. The author has an hindex of 156, co-authored 2342 publications receiving 123391 citations. Previous affiliations of Wolfgang Wagner include University of Pennsylvania & University of Amsterdam.

Search for Higgs boson pair production in the γγWW∗ channel using pp collision data recorded at √s =13 TeV with the ATLAS detector

Abstract: Searches for non-resonant and resonant Higgs boson pair production are performed in the $\gamma \gamma WW^*$ channel with the final state of $\gamma \gamma \ell u jj$ using 36.1 $\hbox {fb}^{-1}$ of proton–proton collision data recorded at a centre-of-mass energy of $\sqrt{s}=$ 13 TeV by the ATLAS detector at the Large Hadron Collider. No significant deviation from the Standard Model prediction is observed. A 95% confidence-level observed upper limit of 7.7 pb is set on the cross section for non-resonant production, while the expected limit is 5.4 pb. A search for a narrow-width resonance X decaying to a pair of Standard Model Higgs bosons HH is performed with the same set of data, and the observed upper limits on $\sigma (pp\rightarrow X)\times B(X\rightarrow HH)$ range between 40.0 and 6.1 pb for masses of the resonance between 260 and 500 GeV, while the expected limits range between 17.6 and 4.4 pb. When deriving the limits above, the Standard Model branching ratios of the $H{\rightarrow }{\gamma \gamma }$ and $H{\rightarrow }WW^*$ are assumed.

Performance study of the CMS barrel resistive plate chambers with cosmic rays

Abstract: In October and November 2008, the CMS collaboration conducted a programme of cosmic ray data taking, which has recorded about 270 million events. The Resistive Plate Chamber system, which is part of the CMS muon detection system, was successfully operated in the full barrel. More than 98% of the channels were operational during the exercise with typical detection efficiency of 90%. In this paper, the performance of the detector during these dedicated runs is reported.

Measurement of the Drell-Yan triple-differential cross section in pp collisions at √{s}=8 TeV

Abstract: This paper presents a measurement of the triple-differential cross section for the Drell-Yan process Z/γ$^{*}$ → l$^{+}$ l$^{−}$ where l is an electron or a muon. The measurement is performed for invariant masses of the lepton pairs, m$_{ll}$ , between 46 and 200 GeV using a sample of 20.2 fb$^{−1}$ of pp collisions data at a centre-of-mass energy of $ \sqrt{s}=8 $ TeV collected by the ATLAS detector at the LHC in 2012. The data are presented in bins of invariant mass, absolute dilepton rapidity, |y$_{ll}$|, and the angular variable cos θ$^{*}$ between the outgoing lepton and the incoming quark in the Collins-Soper frame. The measurements are performed in the range |y$_{ll}$ | < 2.4 in the muon channel, and extended to |y$_{ll}$ | < 3.6 in the electron channel. The cross sections are used to determine the Z boson forward-backward asymmetry as a function of |y$_{ll}$ | and m$_{ll}$ . The measurements achieve high-precision, below the percent level in the pole region, excluding the uncertainty in the integrated luminosity, and are in agreement with predictions. These precision data are sensitive to the parton distribution functions and the effective weak mixing angle.

Top-quark mass measurement from dilepton events at CDF II

Abstract: We report a measurement of the top quark mass using events collected by the CDF II Detector from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron. We calculate a likelihood function for the top mass in events that are consistent with t{bar t} {yields} {bar b}{ell}{sup -}{bar {nu}}{sub {ell}}b{ell}{prime}{sup +}{nu}{sub {ell}}{prime} decays. The likelihood is formed as the convolution of the leading-order matrix element and detector resolution functions. The joint likelihood is the product of likelihoods for each of 33 events collected in 340 pb{sup -1} of integrated luminosity, yielding a top quark mass M{sub t} = 165.2 {+-} 6.1(stat.) {+-} 3.4(syst.) GeV/c{sup 2}. This first application of a matrix-element technique to t{bar t} {yields} b{ell}{sup +}{nu}{sub {ell}}{bar b}{ell}{prime}{sup -}{bar {nu}}{sub {ell}}, decays gives the most precise single measurement of M{sub t} in dilepton events. Combined with other CDF Run II measurements using dilepton events, we measure M{sub t} = 167.9 {+-} 5.2(stat.) {+-} 3.7(syst.) GeV/c{sup 2}.

Measurements of jet vetoes and azimuthal decorrelations in dijet events produced in pp collisions at √s = 7 TeV using the ATLAS detector

Abstract: Additional jet activity in dijet events is measured using pp collisions at ATLAS at a centre-of-mass energy of 7 TeV, for jets reconstructed using the anti-k(t) algorithm with radius parameter R = 0.6. This is done using variables such as the fraction of dijet events without an additional jet in the rapidity interval bounded by the dijet subsystem and correlations between the azimuthal angles of the dijets. They are presented, both with and without a veto on additional jet activity in the rapidity interval, as a function of the scalar average of the transverse momenta of the dijets and of the rapidity interval size. The double differential dijet cross section is also measured as a function of the interval size and the azimuthal angle between the dijets. These variables probe differences in the approach to resummation of large logarithms when performing QCD calculations. The data are compared to POWHEG, interfaced to the PYTHIA 8 and HERWIG parton shower generators, as well as to HEJ with and without interfacing it to the ARIADNE parton shower generator. None of the theoretical predictions agree with the data across the full phase-space considered; however, POWHEG+PYTHIA8 and HEJ+ARIADNE are found to provide the best agreement with the data. These measurements use the full data sample collected with the ATLAS detector in 7 TeV pp collisions at the LHC and correspond to integrated luminosities of 36.1 pb(-1) and 4.5 fb(-1) for data collected during 2010 and 2011, respectively.

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。