16811014
A Water \v{C}erenkov Calorimeter as the Next Generation Neutrino Detector
We propose here a large homogeneous calorimeter as the next generation neutrino detector for $\nu$ factories and/or conventional $\nu$ beams. The active media is chosen to be water for obvious economical reasons. The \v Cerenkov light produced in water is sufficient to have good energy resolution, and the pattern recognition is realized by a modular water tank structure. Monte Carlo simulations demonstrate that the detector performance is excellent for identifying neutrino CC events while rejecting background events.
122214277
A water Cherenkov calorimeter for long baseline neutrino oscillation experiments
Abstract We propose a water-based large homogeneous calorimeter as the next generation neutrino detector for ν factories and/or conventional ν beams. The Cherenkov light produced in water is sufficient to have good energy resolution, and the pattern recognition is realized by a modular water tank structure. Monte Carlo simulations show that the detector performance is excellent for identifying neutrino CC events while rejecting backgrounds.
56005177
Inclusive J production in Z0 decays
Abstract Inclusive J production in Z0 decays is observed via the leptonic decay mode J → l+l− (l = e,μ). We measure the branching ratio Br(Z0 → J + X) = (4.1 ± 0.7 (stat.) ± 0.3 (sys.)) × 10−3. We have calculated the fraction of the J mesons from b-hadron decay and find a branching ratio of Br(b → J + X)= (1.3±0.2(stat.)±0.2(sys.)) × 10−2. We determine the average fractional energy of bottom hadrons 〈XE > = 0.70±0.03 (stat.)+0.02−0.01 (sys.) using the momentum spectrum of the J mesons. From a study of the angle between the J and the most energetic jet, we set an upper limit on the branching ratio Br ( Z 0 → q q g ∗ ; g ∗ → J + X ) −4 at 90% confidence level.
18893994
The mass production and quality control of RPCs for the Daya Bay experiment
Abstract Resistive plate chambers will be used in the Daya Bay reactor neutrino experiment to help veto backgrounds created by cosmic-ray muons. The mass production of RPCs began in 2008 and by the end of 2009, 1600 RPCs (3500 m 2 ) had been produced and tested. This paper describes the production and quality control procedures, and quality assurance using cosmic-ray testing.
118039047
Physics of tau and charm
The physics of tau and charm started in early 70's after J/$\psi$ and $\tau$ were discovered. Since then several dedicated accelerators and experiments were built with increasing luminosities and studies on light hadron spectroscopy, charmonium, electroweak and QCD were never interupted. New interests and surprises are not rare in this area. With the newly built BEPCII/BESIII, an even brighter future is foreseen.
125677069
TUBE CHAMBERS FOR THE MUON FILTER OF THE L3 DETECTOR
118387621
Underground Prototype Water Cherenkov Muon Detector with the Tibet Air Shower Array
We are planning to build a 10,000 m2 water‐Cherenkov‐type muon detector (MD) array under the Tibet air shower (AS) array. The Tibet AS+MD array will have the sensitivity to detect gamma rays in the 100 TeV region by an order of the magnitude better than any other previous existing detectors in the world. In the late fall of 2007, a prototype water Cherenkov muon detector of approximately 100 m2 was constructed under the existing Tibet AS array. The preliminary data analysis is in good agreement with our MC simulation. We are now ready for further expanding the underground water Cherenkov muon detector.
117426890
Age spread in galactic star forming region W3 Main
We present near-infrared JHKs imaging as well as K-band multi-object spectroscopy of the massive stellar content of W3 Main using LUCI at the LBT. We confirm 13 OB stars by their absorption line spectra in W3 Main and spectral types between O5V and B4V have been found. Three massive Young Stellar Objects are identified by their emission line spectra and near-infrared excess. From our spectrophotometric analysis of the massive stars and the nature of their surrounding HII regions we derive the evolutionary sequence of W3 Main and we find an age spread of 2–3 Myr.
121984352
The BES detector
Abstract The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e + e − annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector.
118897040
Deconstructing Baryon Acoustic Oscillations: A Comparison of Methods
The Baryon Acoustic Oscillations (BAOs) or baryon wiggles which are present in the galaxy power spectrum at scales 100-150Mpc/h are powerful features with which to constrain cosmology. The potential of these probes is such that these are now included as primary science goals in the planning of several future galaxy surveys. However, there is not a uniquely defined BAO Method in the literature but a range of implementations. We study the assumptions and cosmological performances of three different BAO methods: the full Fourier space power spectrum [P(k)], the `wiggles only' in Fourier space and the spherical harmonics power spectrum [C(l)]. We contrast the power of each method to constrain cosmology for two fiducial surveys taken from the Dark Energy Task Force (DETF) report and equivalent to future ground and space based spectroscopic surveys. We find that, depending on the assumptions used, the dark energy Figure of Merit (FoM) can change by up to a factor of 35 for a given fiducial model and survey. We compare our results with the DETF implementation and, discuss the robustness of each probe, by quantifying the dependence of the FoM with the wavenumber range. The more information used by a method, the higher its statistical performance, but the higher its sensitivity to systematics and implementations details.
122576647
On muon production and other leakage aspects of pion absorption in a lead/scintillating-fiber calorimeter
Abstract We report on an experimental study of longitudinal leakage phenomena in hadronic shower development. Pions in the energy range of 10–150 GeV were sent into a lead/scintillating-fiber calorimeter with a thickness of 9.6 nuclear interaction lengths. The average fraction of the energy leaking out at the back of this calorimeter ranges from 0.04% at 10 GeV to 0.4% at 150 GeV. This leakage has a very small effect on the hadronic energy resolution. We measured the probability of the creation of escaping muons in the shower development process. This probability ranges from 0.2% at 10 GeV to 2.1% at 150 GeV. Assuming that these muons are produced from π- or K-decay, we find an exponentially decaying muon spectrum with a typical momentum of 2.8 GeV/ c , at 80 GeV incident energy. Also the rates at which hadrons and soft neutrons escape from the calorimeter are measured. Within the acceptance of the leakage calorimeter, neutrons are observed about 10 times as often as muons. Escaping hadrons dominate muons for shower energies above 20 GeV. The experiments were performed at CERN in the framework of the LAA project.