1,103 research outputs found

    N∗N^{\bf *} decays to NωN\omega from new data on γp→ωp\gamma p\to \omega p

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    Data on the reaction γp→ωp\gamma p\to \omega p with ω→π0γ\omega\to\pi^0\gamma, taken with unpolarized or polarized beams in combination with an unpolarized or polarized proton-target, were analyzed within the Bonn-Gatchina (BnGa) partial wave analysis. Differential cross sections, several spin density matrix elements, the beam asymmetry Σ\Sigma, the normalized helicity difference EE, and the correlation GG between linear photon and longitudinal target polarization were included in a large data base on pion and photo-induced reactions. The data on ω\omega photoproduction are used to determine twelve N∗→NωN^*\to N\omega branching ratios; most of these are determined for the first time.Comment: 6 pages, 4 figures, 2 table

    Inocybe woglindeana, a new species of the genus Inocybe, thriving in exposed habitats with calcareous sandy soil

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    Abstract: We describe a smooth-spored species of Inocybe, the basidiomes of which have been encountered growing with Salix in exposed habitats, often with calcareous sandy soils in Germany and Fennoscandia. The species is presented with a detailed description, photographs and microdrawings. Its relationship to similar taxa growing in the same environments is illustrated with ITS and LSU data. Morphologically the species would be keyed out as a member of I. sect. Tardae. For comparison, the types of somewhat similar species occurring in similar habitats as I. woglindeana, i.e. I. subpelargonium, I. rufuloides, I. inodora, I. neorufula and I. variispora, were examined morphologically; from the latter ITS and mtSSU V6 data were obtained. Molecular data supported a very close relationship between I. woglindeana and I. variispora. The two species are also morphologically similar, but differ in colour of pileus, in shape and details of hymenial cystidia, and also in their host and habitat. None of the other species, represented by our own collections or sequences from the public domain, are phylogenetically closely related to I. woglindeana.</p

    Parallelized Incomplete Poisson Preconditioner in Cloth Simulation

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    Efficient cloth simulation is an important problem for interactive applications that involve virtual humans, such as computer games. A common aspect of many methods that have been developed to simulate cloth is a linear system of equations, which is commonly solved using conjugate gradient or multi-grid approaches. In this paper, we introduce to the computer gaming community a recently proposed preconditioner, the incomplete Poisson preconditioner, for conjugate gradient solvers. We show that the parallelized incomplete Poisson preconditioner (PIPP) performs as well as the current state-of-the-art preconditioners, while being much more amenable to standard thread-level parallelism. We demonstrate our results on an 8-core Apple* Mac* Pro and a 32-core code name Emerald Ridge system

    Reproducibility of pulmonary magnetic resonance angiography in adults with muco-obstructive pulmonary disease

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    Background Recent studies support magnetic resonance angiography (MRA) as a diagnostic tool for pulmonary arterial disease. Purpose To determine MRA image quality and reproducibility, and the dependence of MRA image quality and reproducibility on disease severity in patients with chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). Material and Methods Twenty patients with COPD (mean age 66.5 ± 8.9 years; FEV1% = 42.0 ± 13.3%) and 15 with CF (mean age 29.3 ± 9.3 years; FEV1% = 66.6 ± 15.8%) underwent morpho-functional chest magnetic resonance imaging (MRI) including time-resolved MRA twice one month apart (MRI1, MRI2), and COPD patients underwent non-contrast computed tomography (CT). Image quality was assessed visually using standardized subjective 5-point scales. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were measured by regions of interest. Disease severity was determined by spirometry, a well-evaluated chest MRI score, and by computational CT emphysema index (EI) for COPD. Results Subjective image quality was diagnostic for all MRA at MRI1 and MRI2 (mean score = 4.7 ± 0.6). CNR and SNR were 4 43.8 ± 8.7 and 50.5 ± 8.7, respectively. Neither image quality score nor CNR or SNR correlated with FEV1% or chest MRI score for COPD and CF (r = 0.239–0.248). CNR and SNR did not change from MRI1 to MRI2 (P = 0.434–0.995). Further, insignificant differences in CNR and SNR between MRA at MRI1 and MRI2 did not correlate with FEV1% nor chest MRI score in COPD and CF (r = −0.238–0.183), nor with EI in COPD (r = 0.100–0.111). Conclusion MRA achieved diagnostic quality in COPD and CF patients and was highly reproducible irrespective of disease severity. This supports MRA as a robust alternative to CT in patients with underlying muco-obstructive lung disease

    Model-independent extraction of ∣Vtq∣|V_{tq}| matrix elements from top-quark measurements at hadron colliders

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    Current methods to extract the quark-mixing matrix element ∣Vtb∣|V_{tb}| from single-top production measurements assume that ∣Vtb∣≫∣Vtd∣,∣Vts∣|V_{tb}|\gg |V_{td}|, |V_{ts}|: top quarks decay into bb quarks with 100% branching fraction, s-channel single-top production is always accompanied by a bb quark and initial-state contributions from dd and ss quarks in the tt-channel production of single top quarks are neglected. Triggered by a recent measurement of the ratio R=∣Vtb∣2∣Vtd∣2+∣Vts∣2+∣Vtb∣2=0.90±0.04R=\frac{|V_{tb}|^{2}}{|V_{td}|^{2}+|V_{ts}|^{2}+|V_{tb}|^{2}}=0.90 \pm 0.04 performed by the D0 collaboration, we consider a ∣Vtb∣|V_{tb}| extraction method that takes into account non zero d- and s-quark contributions both in production and decay. We propose a strategy that allows to extract consistently and in a model-independent way the quark mixing matrix elements ∣Vtd∣|V_{td}|, ∣Vts∣|V_{ts}|, and ∣Vtb∣|V_{tb}| from the measurement of RR and from single-top measured event yields. As an illustration, we apply our method to the Tevatron data using a CDF analysis of the measured single-top event yield with two jets in the final state one of which is identified as a bb-quark jet. We constrain the ∣Vtq∣|V_{tq}| matrix elements within a four-generation scenario by combining the results with those obtained from direct measurements in flavor physics and determine the preferred range for the top-quark decay width within different scenarios.Comment: 36 pages, 17 figure

    The {\eta}'-carbon potential at low meson momenta

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    The production of η′\eta^\prime mesons in coincidence with forward-going protons has been studied in photon-induced reactions on 12^{12}C and on a liquid hydrogen (LH2_2) target for incoming photon energies of 1.3-2.6 GeV at the electron accelerator ELSA. The η′\eta^\prime mesons have been identified via the η′→π0π0η→6γ\eta^\prime\rightarrow \pi^0 \pi^0\eta \rightarrow 6 \gamma decay registered with the CBELSA/TAPS detector system. Coincident protons have been identified in the MiniTAPS BaF2_2 array at polar angles of 2∘≤θp≤11∘2^{\circ} \le \theta _{p} \le 11^{\circ}. Under these kinematic constraints the η′\eta^\prime mesons are produced with relatively low kinetic energy (≈\approx 150 MeV) since the coincident protons take over most of the momentum of the incident-photon beam. For the C-target this allows the determination of the real part of the η′\eta^\prime-carbon potential at low meson momenta by comparing with collision model calculations of the η′\eta^\prime kinetic energy distribution and excitation function. Fitting the latter data for η′\eta^\prime mesons going backwards in the center-of-mass system yields a potential depth of V = −-(44 ±\pm 16(stat)±\pm15(syst)) MeV, consistent with earlier determinations of the potential depth in inclusive measurements for average η′\eta^\prime momenta of ≈\approx 1.1 GeV/cc. Within the experimental uncertainties, there is no indication of a momentum dependence of the η′\eta^\prime-carbon potential. The LH2_2 data, taken as a reference to check the data analysis and the model calculations, provide differential and integral cross sections in good agreement with previous results for η′\eta^\prime photoproduction off the free proton.Comment: 9 pages, 13 figures. arXiv admin note: text overlap with arXiv:1608.0607
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