Showing papers by "Hermann Kolanoski published in 2008"

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

Abstract: A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.

Multiyear search for a diffuse flux of muon neutrinos with AMANDA-II (vol 76, artn 042008, 2007)

Abstract: A search for TeV-PeV muon neutrinos from unresolved sources was performed on AMANDA-II data collected between 2000 and 2003 with an equivalent live time of 807 days. This diffuse analysis sought to find an extraterrestrial neutrino flux from sources with nonthermal components. The signal is expected to have a harder spectrum than the atmospheric muon and neutrino backgrounds. Since no excess of events was seen in the data over the expected background, an upper limit of E-2 Phi(90%C.L.)< 7.4x10(-8) GeV cm(-2) s(-1) sr(-1) is placed on the diffuse flux of muon neutrinos with a Phi proportional to E-2 spectrum in the energy range 16 TeV to 2.5 PeV. This is currently the most sensitive Phi proportional to E-2 diffuse astrophysical neutrino limit. We also set upper limits for astrophysical and prompt neutrino models, all of which have spectra different from Phi proportional to E-2.

The Search for Muon Neutrinos from Northern Hemisphere Gamma-Ray Bursts with AMANDA

Abstract: We present the results of the analysis of neutrino observations by the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated with photon observations of more than 400 gamma-ray bursts (GRBs) in the northern hemisphere from 1997 to 2003. During this time period, AMANDA's effective collection area for muon neutrinos was larger than that of any other existing detector. After the application of various selection criteria to our data, we expect similar to 1 neutrino event and <2 background events. Based on our observations of zero events during and immediately prior to the GRBs in the data set, we set the most stringent upper limit on muon neutrino emission correlated with GRBs. Assuming a Waxman-Bahcall spectrum and incorporating all systematic uncertainties, our flux upper limit has a normalization at 1 PeV of E-2 Phi(nu) <= 6.3 x 10(-9) GeV cm(-2) s(-1) sr(-1), with 90% of the events expected within the energy range of similar to 10 TeV to similar to 3 PeV. The impact of this limit on several theoretical models of GRBs is discussed, as well as the future potential for detection of GRBs by next-generation neutrino telescopes. Finally, we briefly describe several modifications to this analysis in order to apply it to other types of transient point sources.

Observation of Polarized Positrons from an Undulator-Based Source

Abstract: An experiment (E166) at the Stanford Linear Accelerator Center has demonstrated a scheme in which a multi-GeV electron beam passed through a helical undulator to generate multi-MeV, circularly polarized photons which were then converted in a thin target to produce positrons (and electrons) with longitudinal polarization above 80% at 6 MeV. The results are in agreement with GEANT4 simulations that include the dominant polarization-dependent interactions of electrons, positrons, and photons in matter.

Solar Energetic Particle Spectrum on 2006 December 13 Determined by IceTop

Abstract: On 2006 December 13 the IceTop air shower array at the South Pole detected a major solar particle event. By numerically simulating the response of the IceTop tanks, which are thick Cerenkov detectors with multiple thresholds deployed at high altitude with no geomagnetic cutoff, we determined the particle energy spectrum in the energy range 0.6-7.6 GeV. This is the first such spectral measurement using a single instrument with a well-defined viewing direction. We compare the IceTop spectrum and its time evolution with previously published results and outline plans for improved resolution of future solar particle spectra.

Cosmic Ray Results from the IceTop Air Shower Array

Abstract: We report on the first results obtained with the IceTop air shower array on the cosmic ray energy spectrum and mass composition in the range of 1 PeV to 80 PeV. IceTop is the surface detector of the IceCube neutrino telescope currently under construction at the South Pole. A high sensitivity to the primary mass composition was observed by reconstructing showers at different zenith angles. Assuming only protons or iron nuclei as primary particles yields significantly different energy spectra for different zenith angle ranges, while only models with mixed composition, like the poly-gonato model, lead to the expected isotropic flux. The prospects of composition measurements with different, alternative methods using the full IceCube detector are also discussed.

Lateral Distribution of Air Shower Signals and Initial Energy Spectrum above 1 PeV from IceTop

Abstract: In a method for manufacturing a master disc for optical discs, patterns to be displayed on the disc are classified into a main object and a background. The background is commonly assigned as the background pattern for glittering rainbow colors by diffracted light reflected from dummy pits of diffraction gratings or a hologram. The main object is individually assigned as the main object pattern of a diffused reflection portion or mirror surface. The manufacturing method comprises one group of steps for forming the common background pattern and the other group of steps for forming the individual main object pattern in the common background pattern. A development substrate for the master disc is formed by using a mask disc in a first light-exposure of a photoresist layer thereof and by using a displaying-pattern mask in a first light-exposure of the photoresist layer. The individual main object pattern is drawn in the common background pattern of the master disc by using a laser-marking or an etching. The mask disc and displaying-pattern mask can be used repeatedly as families for the background and main object patterns so as to facilitate the replication of the optical discs.

Search for the Flavor-Changing Neutral Current Decay D 0 ! + with the HERA-B Detector

Abstract: Abstract We report on a search for the flavor-changing neutral current decay D 0 → μ + μ − using 50 × 10 6 events recorded with a dimuon trigger in interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find no evidence for such decays and set a 90% confidence level upper limit on the branching fraction B ( D 0 → μ + μ − ) 2.0 × 10 − 6 .

IceCube contributions to the XIV International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2006). Weihai, China - August 15-22

Abstract: IceCube contributions to the XIV International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2006) Weihai, China - August 15-22