120667839
Study of the granularity for a tracking calorimeter with optimal rejection of proton background in positron detection
SummaryIn this paper we present a Monte Carlo study of a calorimeter response for an experiment to equip the magnetic facility of the USA space station. Main purpose in the design of such a calorimeter is the efficient discrimination between eloctromagnetic and hadronic showers. The estimated rejection power results to be better than 1·10−3 p/e+ for incident particles with energy between 10 GeV and 100GeV.RiassuntoIn questo lavoro presentiamo lo studio, realizzato con un metodo di Monte Carlo, della risposta di un calorimetro progettato per un esperimento da inserire nel magnete della stazione spaziale USA. Il principale obiettivo, considerato nel progetto di questo calorimetro, è l’efficiente discriminazione tra sciami elettromagnetici e adronici. Il potere di reiezione è stimato migliore di 1·10−3p/e+ per energie delle particelle incidenti da 10 GeV a 100 GeV.РезюмеВ этой работе мы предлагаем исследование по методу Монте-Карло отклика калориметра, который сконструирован для экспериментов на космической станции США. Основная цель при конструировании такого калориметра заключается в эффективной дискриминации между электромагнитными и адронными ливнями. Оценивается степень устранения фона протонов, которая оказывается лучше, чем 1·10−3 p/e+ для падающих частиц с энергиями между 10 ГэВ и 100 ГэВ.
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.
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.
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.
125677069
TUBE CHAMBERS FOR THE MUON FILTER OF THE L3 DETECTOR
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.
118369110
Towards a Holographic Description of Inflation and Generation of Fluctuations from Thermodynamics
Recently, Verlinde conjectured that gravity may be an entropic force, arising from thermodynamics on the holographic screen. We investigate the implications of the entropic force conjecture for inflationary cosmology. We find the background dynamics of inflation can be dually described in the holographic language. At the perturbation level, two kinds of novel scale invariant scalar fluctuations arise from thermal fluctuations on the holographic screen. These fluctuations can be responsible for CMB anisotropy and structure formation.
17382364
The Cross-Correlation between Galaxies of Different Luminosities and Colors
We study the cross-correlation between galaxies of different luminosities and colors, using a sample of 284,489 galaxies selected from SDSS DR4. Galaxies are divided into six samples according to luminosity, and each of these samples is further divided into red and blue subsamples according to their (g-r) colors. Projected autocorrelation is estimated for each subsample, and projected cross-correlation is estimated for each pair of subsamples. At projected separations r(p) greater than or similar to 1 h(-1) Mpc, all correlation functions are roughly parallel, although the correlation amplitude depends systematically on both luminosity and color. On r(p) less than or similar to 1 h(-1) Mpc, the autocorrelation and cross- correlation functions of red galaxies are significantly enhanced relative to the corresponding power laws obtained on larger scales. Such enhancement is absent for blue galaxies and in the cross- correlation between red and blue galaxies. We estimate the relative bias factor on scales r(p) greater than or similar to 1 h(-1) Mpc for each subsample using its autocorrelation function as well as its cross-correlation functions with other subsamples. The relative bias factors obtained from different methods are similar. For blue galaxies the luminosity dependence of the relative bias is strong over the entire luminosity range probed (-23.0 < M-r <= -18.0), while for red galaxies the dependence is weaker and becomes insignificant for luminosities below L*. In order to examine whether a significant stochastic/nonlinear component exists in the bias relation, we study the ratio R-ij equivalent to WiiWjj/W-ij(2), where W-ij is the projected correlation between subsample "i" and "j." Results suggest that a significant stochastic/nonlinear component exists in the relationship between red and blue galaxies, particularly on small scales.
105027497
In-situ hydrothermal synthesis using 13-BM-D at the APS
121694828
Performance of prototypes for the ALICE electromagnetic calorimeter
Abstract The performance of prototypes for the ALICE electromagnetic sampling calorimeter has been studied in test beam measurements at FNAL and CERN. A 4 × 4 array of final design modules showed an energy resolution of about 11 % / E ( GeV ) ⊕ 1.7 % with a uniformity of the response to electrons of 1% and a good linearity in the energy range from 10 to 100 GeV. The electromagnetic shower position resolution was found to be described by 1.5 mm ⊕ 5.3 mm / E ( GeV ) . For an electron identification efficiency of 90% a hadron rejection factor of > 600 was obtained.
123257721
The stringless gauge potential of accelerated monopole
SummaryIn this paper, we get theU1 potential without singular string for an accelerated magnetic pole. To obtain this we find its equivalentSU2 potential, which could be expressed by anU1-invariant section of theSU2/U1 coset bundle. Then we could superpose linearly the correspondingU1 potentials to get the potential of an accelerated system of monopoles and electric charges in the general case. By the way, we also discuss the criterion forU1 field to be in one-to-one correspondence with anU1-invariant section and the condition for aSU2 field to be reducible to anU1 field.RiassuntoIn questo lavoro si ottiene il potenzialeU1 senza stringa singolare per un monopolo magnetico accelerato. Per ottenerlo si trova il suo potenziale equivalenteSU2, che può essere espresso mediante una sezione invariante rispetto aU1 del fascio del coinsiemeSU2/U1. Si piò allora sovrapporre linearmente i corrispondenti potenzialiU1 per ottenere il potenziale del sistema accelerato di monopoli e le cariche elettriche nel caso generale. A questo proposito, si discute anche il criterio per cui il campoU1 è in corrispondenza 1-1 con una sezione invariante rispetto aU1 e la condizione per cui un campoSU2 è riducibile ad un campoU1.РезюмеВ этой статье мы получаемU1 потенциал без сингулярной струны для ускоренного монополя. Для получения этого потенциала мы находим эквивалентный емуSU2 потенциал, который может быть выражен черезU1 инвариантное сечениеSU2/U1 семейства смежного класса. Затем мы получаем линейную суперпозицию соответствующихU1 потенциалов, чтобы получить потенциал для ускоренной системы монополей и электрических зарядов в общем случае, мы также обсуждаем критерий, чтобы полеU1 находилось в однозначном соответствии сU1 инвариантным сечением, и условие, чтобы полеSU2 могло быть сведено к полюU1.