18453536
Atmospheric neutrino induced muons in the MACRO detector
A measurement of the flux of neutrino-induced muons using the MACRO detector is presented. Different event topologies, corresponding to different neutrino parent energies can be detected. The upward throughgoing muon sample is larger event sample. For this sample, produced by neutrinos having an average energy around 100 GeV, the ratio of the number of observed to expected events integrated over all zenith angles is 0.74 ± 0.036stat ± 0.046syst ± 0.13theor. We have investigated whether the observed number of events and the shape of the zenith distribution can be explained by an hypothesis of νμ → ντ oscillation. The best probability (17%) is obtained for sin2 2θ ≅ 1.0 and Δm2 of a few times 10−3 eV2, while the probability for the no oscillation hypothesis is 0.1%. The other samples are due to the internally produced events and to upward-going stopping muons; the average parent neutrino energy is of the order of 4 GeV. The low energy data sets show a deficit of observed events similar to the one predicted by the oscillation model with maximum mixing suggested from the upward throughgoing muon sample.
121773371
Muon tracking underground
SummaryWe present a new design of plastic streamer tubes, optimized to match the experimental requirements of large-area under-ground detectors, where muon identification is needed with good angular resolution.RiassuntoSi descrive un nuovo disegno di tubi a streamer in plastica, ottimizzati per le esigenze sperimentali di apparati sotterranei di grande area, dove si richiede l'identificazione di muoni con buona risoluzione angolare.РзюмеПредлагается новый проект пластических стримерных трубок, оптимально согласованный с эксперименталыми требованиями подэемных детекторов на большой площади, когда небходима идентификция мюоноб с высокими угловым разрешением.
118375535
Comparison of muon and neutrino times from decays of mesons in the atmosphere
We propose a test to compare the speed of muons and muon neutrinos produced in the same bundles in the atmosphere. By comparing the arrival times of primary muons and muons induced by neutrinos, experiments such as Super-Kamiokande, IceCube and ANTARES could verify recent hints on the possibility that neutrinos have a velocity larger than the speed of light. For smaller detectors such as MINOS and OPERA, where it may be challenging to recognize downgoing muons induced by neutrinos inside the active volume, another measurement may be possible thanks to the ns-time resolution. The arrival times of muons in a bundle produced by one cosmic ray interaction in the atmosphere should return a value compatible with the time resolution, while if neutrinos have larger velocity than muons some of the muons may arrive slightly earlier in a bundle of particles than others.
122862116
EXPLORER and NAUTILUS gravitational wave detectors: a status report
The two cryogenic resonant bar detectors of the ROG Collaboration, EXPLORER and NAUTILUS, have been taking data continuously with a high duty cycle for several years. We report here on the status of recent analysis of the data and in particular on the results of the burst searches in the year 2004.
8791824
Detection of high energy cosmic rays with the resonant gravitational wave detectors NAUTILUS and EXPLORER
Abstract The cryogenic resonant gravitational wave detectors NAUTILUS and EXPLORER, made of an aluminum alloy bar, can detect cosmic ray showers. At temperatures above 1 K, when the material is in the normal-conducting state, the measured signals are in good agreement with the expected values based on the cosmic rays data and on the thermo-acoustic model. When NAUTILUS was operated at the temperature of 0.14 K, in superconductive state, large signals produced by cosmic ray interactions, more energetic than expected, were recorded. The NAUTILUS data in this case are in agreement with the measurements done by a dedicated experiment on a particle beam. The biggest recorded event was in EXPLORER and excited the first longitudinal mode to a vibrational energy of ∼670 K, corresponding to ∼360 TeV absorbed in the bar. Cosmic rays can be an important background in future acoustic detectors of improved sensitivity. At present, they represent a useful tool to verify the gravitational wave antenna performance.
59335104
RAP: thermoacoustic detection at the DAΦNE beam test facility
In order to investigate the anomalous response at ultra-low temperatures of the resonant-mass gravitational wave detector NAUTILUS, the RAP experiment has been planned to measure the vibrations in a small cylindrical aluminium bar when hit by 105 510 MeV electrons from the DAΦNE beam test facility, corresponding to the energies released by typical extensive air showers. The results of the measurement at low temperature and in the superconducting regime are crucial to understand the interaction of ionizing particles with bulk superconductors and to confirm the results on the thermoacoustic model of the past experiments. The first run of RAP experiment is scheduled for the end of June. The scheme of operation and the preliminary results at room temperature will be presented.
122705388
Measurement of the Muon Stopping Power in Lead Tungstate
A large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in lead tungstate is measured to be 160+5/-6 plus or minus 8 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy.
122796602
Performance of the CMS cathode strip chambers with cosmic rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in 
the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray 
run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 
1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 µm to 
243 µm. The efficiencies for local charged track triggers, for hit and for segments reconstruction 
were measured, and are above 99%. The timing resolution per layer is approximately 5 ns.
209834924
Performance of CMS Muon Reconstruction in Cosmic-Ray Events
The performance of muon reconstruction in CMS is evaluated using a large data sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured for a broad range of muon momenta, and were found to be in good agreement with expectations from Monte Carlo simulation. The relative momentum resolution for muons crossing the barrel part of the detector is better than 1% at 10 GeV/c and is about 8% at 500 GeV/c, the latter being only a factor of two worse than expected with ideal alignment conditions. Muon charge misassignment ranges from less than 0.01% at 10 GeV/c to about 1% at 500 GeV/c.
119371614
Computing System for the Belle Experiment
We describe the offline computing system of the Belle experiment, consisting of a computing farm with one thousand IA-32 CPUs. Up to now, the Belle experiment has accumulated more than 120 fb$^{-1}$ of data, which is the world largest $B\bar{B}$ sample at the $\Upsilon(4S)$ energy. The data have to be processed with a single version of reconstruction software and calibration constants to perform precise measurements of $B$ meson decays. In addition, Monte Carlo samples three times larger than the real beam data are generated. To fullfill our computing needs, we have constructed the computing system with 90(300) quad(dual) CPU PC servers from multiple vendors as a central processing system. The details of this computing system and performance of data processing with the current model are presented.
200108193
Time-dependent CP asymmetries in b ---> s anti-q q transitions and sin 2 phi(1) in B0 ---> j/psi K0 decays with 386 million B anti-B pairs