122914096
The design and mass production on resistive plate chambers for the BESIII experiment
A new type of the phenolic paper laminate is used as the resistive electrodes of BESIII RPC. The surface smoothness of these laminates is comparable to that of the bakelite plates with linseed oil treating. A technique to adjust the bulk resistivity of the laminates within the range of 10 9 –10 13 O cm is developed. Nowadays, about 1000 bare chambers (1200 m 2 ) have been produced and used for BESIII MUON, and the rejection rate is only 1.5%. In this paper, we will discuss the mass production and quality control procedures of these RPCs. r 2007 Elsevier B.V. All rights reserved. PACS: 29.40.n; 29.30.Cs
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.
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.
125677069
TUBE CHAMBERS FOR THE MUON FILTER OF THE L3 DETECTOR
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.
13502894
Beam test results of two kinds of high-rate multi-gap resistive plate chambers
To improve the rate capability of MRPC, we developed pad- and strip-readout multi-gap resistive plate chambers (MRPCs) with low-resistive silicate glass electrodes (with bulk resistivity of 1010Ωcm quantity) and studied their performances. The tests were performed with 2.5GeV proton beam at GSI. Time resolutions below 85ps and efficiencies larger than 90% were obtained at counting rates up to 28 kHz/cm2.
54774628
New prototype multi-gap resistive plate chambers with long strips
A new kind of Multi-gap Resistive Plate Chamber (MRPC) has been built for the large-area Muon Telescope Detector (MTD) for the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). These long read-out strip Multi-gap Resistive Plate Chambers (LMRPCs) have an active area of 87.0 � 17.0 cm 2 and ten 250mm-thick gas gaps arranged as a double stack. Each read-out strip is 2.5 cm wide and 90 cm long. The signals are read-out at both ends of each strip. Cosmic ray tests indicate a time resolution of � 70 ps and a detection efficiency of greater than 95%. Beam tests performed at T963 at Fermilab indicate a time resolution of 60–70 ps and a spatial resolution of � 1 cm along the strip direction. & 2008 Elsevier B.V. All rights reserved.
14695790
String Gas Cosmology and Non-Gaussianities
Recently it has been shown that string gas cosmology, an alternative model of the very early universe which does not involve a period of cosmological inflation, can give rise to an almost scale invariant spectrum of metric perturbations. Here we calculate the non-Gaussianities of the spectrum of cosmological fluctuations in string gas cosmology, and find that these non-Gaussianities depend linearly on the wave number and that their amplitude depends sensitively on the string scale. If the string scale is at the TeV scale, string gas cosmology could lead to observable non-Gaussianities, if it is close to the Planck scale, then the non-Gaussianities on current cosmological scales are negligible.
15565815
Aerogel Cherenkov counter for the BELLE experiment
In the BELLE experiment at KEKB, a threshold Cherenkov counter system based on silica aerogels will be used to provide πK separation in the momentum region from 0.8 to 3.5 GeV/c. The detector design, recent progress in R&D and results of beam tests are reviewed.
119282054
Discriminating Different $Z^\prime$s via Asymmetries at the LHC
In practice the asymmetry, which is defined based on the angular distribution of the final states in scattering or decay processes, can be utilized to scrutinize underlying dynamics in and/or beyond the standard model (BSM). As one of the possible BSM physics which might be discovered early at the LHC, extra neutral gauge bosons Z{sup '}'s are theoretically well motivated. Once Z{sup '}'s are discovered at the LHC, it is crucial to discriminate different Z{sup '}'s in various BSM. In principle such a task can be accomplished by measuring the angular distribution of the final states which are produced via Z{sup '}-mediated processes. In the real data analysis, asymmetry is always adopted. In the literature several asymmetries have been proposed at the LHC. Based on these works, we stepped further on to study how to optimize the asymmetries in the left-right model and the sequential standard model, as the examples of BSM. In this paper, we examined four kinds of asymmetries, namely, rapidity-dependent forward-backward asymmetry, oneside forward-backward asymmetry, central charge asymmetry, and edge charge asymmetry (see text for details), with l{sup +}l{sup -} (l=e, {mu}), bb, and tt as the final states. In the calculations with bb and tt finalmore » states, the QCD-induced higher-order contributions to the asymmetric cross section were also included. For each kind of final state, we estimated the four kinds of asymmetries and especially the optimal cut usually associated with the definition of the asymmetry. Our numerical results indicated that the capacity to discriminate Z{sup '} models can be improved by imposing the optimal cuts.« less