1,912 research outputs found

    Engineering Study of the SIS100 Radiation Resistant Quadrupole Magnet Environment

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    Investigation of the Lightest Hybrid Meson Candidate with a Coupled-Channel Analysis of pˉp\bar{p}p-, πp\pi^- p- and ππ\pi\pi-Data

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    Based on new insights from two recent coupled-channel analyses of pˉp\bar{p}p annihilation together with ππ\pi\pi-scattering data and of πp\pi^- p data, this paper aims at a better understanding of the spin-exotic π1\pi_1 resonances in the light meson sector. The Crystal Barrel Collaboration observed the π1\pi_1-wave in pˉp\bar{p}p annihilations in flight for the first time with the coupling to π0η\pi^0\eta in the reaction pˉpπ0π0η\bar{p}p\,\rightarrow\,\pi^0\pi^0\eta with a sophisticated coupled-channel approach. Another refined coupled-channel analysis of the P- and D-waves in the πη\pi\eta and πη\pi\eta^\prime system based on data measured at COMPASS has been performed by the JPAC group. In that study the two spin-exotic signatures listed in the PDG, the π1(1400)\pi_1(1400) and π1(1600)\pi_1(1600), with a separate coupling to πη\pi\eta and πη\pi\eta^\prime can be described by a single pole. In this paper, both analyses, the one with the three pˉp\bar{p}p annihilation channels into π0π0η\pi^0\pi^0\eta, π0ηη\pi^0\eta\eta and K+Kπ0K^+K^-\pi^0 and 11 different ππ\pi\pi-scattering data sets and the one with the P- and D-wave data in the πη\pi\eta and πη\pi\eta^\prime systems measured at COMPASS, are subjected to a combined coupled channel analysis. By utilizing the K-matrix approach and realizing the analyticity via Chew-Mandelstam functions the π1\pi_1 wave can be well described by a single pole for both systems, πη\pi\eta and πη\pi\eta^\prime. The mass and width of the π1\pi_1-pole are measured to be (1561.6 \, \pm \, 3.0 \, ^{+6.6}_{-2.6}\,)\, \mathrm{MeV/c}^2 and (388.1 \, \pm \, 5.4 \, ^{+0.2}_{-14.1}\,)\, \mathrm{MeV}.Comment: 5 pages, 2 figures, 1 tabl

    A Portable TV-Holography (ESPI) System for QNDE

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    Quantitative nondestructive evaluation of structures is achieved by this remote sensing technique which measures the deformation vector components of a surface in all 3 dimensions. Traditional techniques involve predominantly the application of strain gauges for the two in-plane deformation vector components. This technique unfortunately only reveals the in-plane deformation between two distinct points where the strain gauge is glued onto the surface. Interferometric techniques on the other hand are most common to measure the out-of-plane deformation component. Conventional film or thermoplastic holography is one of the most sensitive among those techniques measuring out-of-plane deformations in the micron and submicron range. One major disadvantage of this technique is the low time-resolution due to the fact that it involves the processing of photographic or thermoplastic film.</p

    Spin density matrix of the ω in the reaction p¯p→ωπ0

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    The spin density matrix of the ω has been determined for the reaction p¯p→ωπ0 with unpolarized in-flight data measured by the Crystal Barrel LEAR experiment at CERN. The two main decay modes of the ω into π0γ and π+π-π0 have been separately analyzed for various p¯ momenta between 600 and 1940 MeV/c. The results obtained with the usual method by extracting the matrix elements via the ω decay angular distributions and with the more sophisticated method via a full partial wave analysis are in good agreement. A strong spin alignment of the ω is clearly visible in this energy regime and all individual spin density matrix elements exhibit an oscillatory dependence on the production angle. In addition, the largest contributing orbital angular momentum of the p¯p system has been identified for the different beam momenta. It increases from Lp¯pmax = 2 at 600 MeV/c to Lp¯pmax = 5 at 1940 MeV/c

    Caloric dose-responsive genes in blood cells differentiate the metabolic status of obese men.

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    We have investigated the postprandial transcriptional response of blood cells to increasing caloric doses of a meal challenge to test whether the dynamic response of the human organism to the ingestion of food is dependent on metabolic health. The randomized crossover study included seven normal weight and seven obese men consuming three doses (500/1000/1500 kcal) of a high-fat meal. The blood cell transcriptome was measured before and 2, 4, and 6 h after meal ingestion (168 samples). We applied univariate and multivariate statistics to investigate differentially expressed genes in both study groups. We identified 624 probe sets that were up- or down-regulated after the caloric challenge in a dose-dependent manner. These transcripts were most responsive to the 1500 kcal challenge in the obese group and were associated with postprandial insulin and oxidative phosphorylation. Furthermore, the data revealed a separation of the obese group into individuals whose response was close to the normal weight group and individuals with a transcriptional response indicative of a loss of metabolic flexibility. The molecular signature provided by the postprandial transcriptomic response of blood cells to increasing caloric doses of a high-fat meal challenge may represent a sensitive way to evaluate the qualitative impact of food on human health

    Report and preliminary results of R/V POSEIDON cruise POS500, LISA, Ligurian Slope AUV mapping, gravity coring and seismic reflection, Catania (Italy) – Malaga (Spain), 25.05.2016 – 09.06.2016

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    Cruise POS500 “LISA” with R/V Poseidon studied the western Ligurian Margin off Southern France, an area in the northeastern part of the western Mediterranean Sea characterized by its active tectonism and frequent mass wasting. The region near the Var estuary close to the city of Nice is particularly suited for landslide research because it represents a natural laboratority where it is possible to study a series of trigger processes of geological and anthropogenic origin. The aim of this MARUM expedition was to: i. Study fresh water seepage in the marine Nice airport landslide and adjacent stable plateau in 15-50 m water depth using water sampling, CTD and geochemistry; ii. Recover and deploy a number of observatories that monitor, pressure, temperature, tilt and seismicity; iii. Run an AUV micro-bathymetric survey with MARUM AUV SEAL5000 to complement existing multibeam maps; and iv. Acquire additional high-resolution seismic reflection profiles to unravel the complex architecture of the Nice slope and Var delta. In a period of approximately two weeks, we acquired valuable geophysical information that helps to understand the evolution of this portion of the Ligurian Margin and further to support an active Amphibious Drilling proposal submitted to ICDP and IODP. We could also show that heavy spring rainfall plus melt water from the French Maritime Alps supplied sufficient hydraulic forcing to push Var aquifer groundwaters to seep into the marine deposits and water column. Freshening was strongest in the 1979 Nice landslide scar, but was also found at the outer edge of the shelf. Recovery and redeployment of various observatory prototypes worked well, both for the MARUM MeBo seafloor drillstring tolos and independent piezometers. Observatory data have yet to be evaluated. In addition, geochemical analyses of bottom waters and pore waters was deferred to shore-based laboratorios except for salinity estimates using a refractometer. Seismic processing was started onboard, but is largely taking place post-cruise at University Bremen

    Reactions at polymer interfaces: A Monte Carlo Simulation

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    Reactions at a strongly segregated interface of a symmetric binary polymer blend are investigated via Monte Carlo simulations. End functionalized homopolymers of different species interact at the interface instantaneously and irreversibly to form diblock copolymers. The simulations, in the framework of the bond fluctuation model, determine the time dependence of the copolymer production in the initial and intermediate time regime for small reactant concentration ρ0Rg3=0.163...0.0406\rho_0 R_g^3=0.163 ... 0.0406. The results are compared to recent theories and simulation data of a simple reaction diffusion model. For the reactant concentration accessible in the simulation, no linear growth of the copolymer density is found in the initial regime, and a t\sqrt{t}-law is observed in the intermediate stage.Comment: to appear in Macromolecule

    Modification of the ω\omega-Meson Lifetime in Nuclear Matter

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    The photo production of ω\omega mesons on the nuclei C, Ca, Nb and Pb has been measured using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the ω\omega meson cross section on the nuclear mass number has been compared with three different types of models, a Glauber analysis, a BUU analysis of the Giessen theory group and a calculation by the Valencia theory group. In all three cases, the inelastic ω\omega width is found to be 130150MeV/c2130-150 \rm{MeV/c^2} at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the restframe of the ω\omega meson, this inelastic ω\omega width corresponds to a reduction of the ω\omega lifetime by a factor 30\approx 30. For the first time, the momentum dependent ω\omegaN cross section has been extracted from the experiment and is in the range of 70 mb.Comment: 5 pages, 4 figure

    Parallel Excluded Volume Tempering for Polymer Melts

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    We have developed a technique to accelerate the acquisition of effectively uncorrelated configurations for off-lattice models of dense polymer melts which makes use of both parallel tempering and large scale Monte Carlo moves. The method is based upon simulating a set of systems in parallel, each of which has a slightly different repulsive core potential, such that a thermodynamic path from full excluded volume to an ideal gas of random walks is generated. While each system is run with standard stochastic dynamics, resulting in an NVT ensemble, we implement the parallel tempering through stochastic swaps between the configurations of adjacent potentials, and the large scale Monte Carlo moves through attempted pivot and translation moves which reach a realistic acceptance probability as the limit of the ideal gas of random walks is approached. Compared to pure stochastic dynamics, this results in an increased efficiency even for a system of chains as short as N=60N = 60 monomers, however at this chain length the large scale Monte Carlo moves were ineffective. For even longer chains the speedup becomes substantial, as observed from preliminary data for N=200N = 200
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