The J- and H-bands of dye aggregate spectra: Analysis of the coherent exciton scattering (CES) approximation

The validity of the CES approximation is investigated by comparison with direct diagonalisation of a model vibronic Hamiltonian of $N$ identical monomers interacting electronically. Even for quite short aggregates (N\gtrsim 6) the CES approximation is shown to give results in agreement with direct diagonalisation, for all coupling strengths, except that of intermediate positive coupling (the H-band region). However, previously excellent agreement of CES calculations and measured spectra in the H-band region was obtained [A. Eisfeld, J. S. Briggs, Chem. Phys. 324, 376]. This is shown to arise from use of the measured monomer spectrum which includes implicitly dissipative effects not present in the model calculation

The First VERITAS Telescope

The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.Comment: Accepted by Astroparticle Physic

The PHENIX Experiment at RHIC

The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

Angular analysis of the decay B0→K*0μ+μ- from pp collisions at s=8 TeV

The angular distributions and the differential branching fraction of the decay B0→K⁎(892)0μ+μ− are studied using data corresponding to an integrated luminosity of 20.5 fb −1 collected with the CMS detector at the LHC in pp collisions at s=8 TeV . From 1430 signal decays, the forward–backward asymmetry of the muons, the K⁎(892)0 longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions

Search for the production of an excited bottom quark decaying to tW in proton-proton collisions at root s=8 TeV

Peer reviewe

Search for supersymmetry in the vector-boson fusion topology in proton-proton collisions at √s = 8 TeV

The first search for supersymmetry in the vector-boson fusion topology is presented. The search targets final states with at least two leptons, large missing transverse momentum, and two jets with a large separation in rapidity. The data sample corresponds to an integrated luminosity of 19.7 fb −1 of proton-proton collisions at s = 8 s√=8 TeV collected with the CMS detector at the CERN LHC. The observed dijet invariant mass spectrum is found to be consistent with the expected standard model prediction. Upper limits are set on the cross sections for chargino and neutralino production with two associated jets, assuming the supersymmetric partner of the τ lepton to be the lightest slepton and the lightest slepton to be lighter than the charginos. For a so-called compressed-mass-spectrum scenario in which the mass difference between the lightest supersymmetric particle χ ˜ 1 0 χ~01 and the next lightest, mass-degenerate, gaugino particles χ ˜ 2 0 χ~02 and χ ˜ 1 ± χ~±1 is 50 GeV, a mass lower limit of 170 GeV is set for these latter two particles

Immersive Co-production to Inform Ranch Management in Gunnison, Colorado, USA

To be successful, producers must interpret environmental stimuli and respond with management actions that help match their production operations to the ecosystem services they depend on. Climate change, and the increased variability that will likely result, may lessen the relevance of historical rules of thumb and management heuristics by altering environmental conditions and giving rise to novel systems that feature more frequent and intense periods of stress. Sustaining livestock production in the face of climate change depends on the rapid production of knowledge to inform adaptation to novel systems. Involving producers in research is often discussed as a strategy to help accomplish this goal. We propose immersive co-production, wherein a student researcher is embedded within the production operations of a working ranch while studying and conducting research, as one method of quickly developing the knowledge resources necessary to sustain livestock production in the context of environmental change. We present a case study involving a ranch near Gunnison, Colorado, as evidence of the effectiveness of this approach. Immersive co-production involves producers in research and researchers in production to develop useful ranch-level management insights and a new generation of interdisciplinary range professionals with intimate knowledge of the complexity faced by producers.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Hot-fire testing of liquid oxygen/hydrogen single coaxial injector at high-pressure conditions with optical diagnostics

Injector behavior is of utmost importance for the performance and stability of liquid rocket engines (LREs). A major problem is getting a highly efficient homogeneous mixture and effective chemical reaction of fuels at minimum chamber length. Despite substantial progress in numerical simulations, a need for experimental data at representative conditions for development and validation of numerical design tools still exists. Therefore, in the framework of the DLR-project “ProTau,” the authors have performed tests to create an extended data base for numerical tool validation for high-pressure liquid oxygen (LOx) / hydrogen combustion. During the experimental investigations, a windowed DLR subscale thrust chamber model “C” (designated BKC) has been operated over a broad range of conditions at reduced pressures of approximately 0.8 (4 MPa), 1 (5 MPa), and 1.2 (6 MPa) with respect to the thermodynamic critical pressure of oxygen. Liquid oxygen and gaseous hydrogen (GH2) have been injected through a single coaxial injector element at temperatures of ~ 120 and ~ 130 K, respectively. High-speed optical diagnostics have been implemented, including imaging of OH* emission and shadowgraph imaging at frequencies from 8 up to 10 kHz to visualize the flow field