132 research outputs found
Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV
The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3
magnetic muon spectrometer for zenith angles ranging from 0 degree to 58
degree. Due to the large exposure of about 150 m2 sr d, and the excellent
momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in
the vertical direction is achieved.
The ratio of positive to negative muons is studied between 20 GeV and 500
GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003
(stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
Precison Measurements of the Mass, the Widths of Resonance and the Cross Section at GeV
By analyzing the values measured at 68 energy points in the energy region
between 3.650 and 3.872 GeV reported in our previous paper, we have precisely
measured the mass, the total width, the leptonic width and the leptonic decay
branching fraction of the to be MeV, MeV,
eV and , respectively, which result in
the observed cross section nb at MeV. We have also measured for the continuum light hadron production in the
region from 3.650 to 3.872 GeV.Comment: 5 pages, 2 figure
Measurement of \chi_cJ--> K+K-K+K-
Using 14M psi(2S) events taken with the BES-II detector, chi_cJ-->K+K-K+K-
decays are studied. For the four-kaon final state, the branching fractions are
B(chi_c0,1,2 -->K+K-K+K-)=(3.48\pm 0.23\pm 0.47)\times 10^{-3}, (0.70\pm
0.13\pm 0.10)\times 10^{-3}, and (2.17\pm 0.20\pm 0.31)\times 10^{-3}. For the
\phi K+K- final state, the branching fractions, which are measured for the
first time, are B(chi_c0,1,2-->\phi K+K-)=(1.03\pm 0.22\pm 0.15)\times 10^{-3},
(0.46\pm 0.16\pm 0.06)\times 10^{-3}, and (1.67\pm 0.26\pm 0.24)\times 10^{-4}.
For the \phi\phi final state, B(chi_{c0,2}-->\phi\phi)=(0.94\pm 0.21\pm
0.13)\times 10^{-3} and (1.70\pm 0.30\pm 0.25)\times 10^{-3}.Comment: 7 pages, 7 figure
Global cooling controls on the chemical weathering as evidenced from the Plio-Pleistocene deposits of the North China Plain
Effects of fertilization on the growth, photosynthetic characteristics and yield of Coffea Arabica
Coffea arabica is a major economic plant in agriculture plantation in tropical and subtropical areas in the world. This paper reports the experimental results on the fertilization strategy in Yunnan, China. Effects of varied levels of nitrogen (N), phosphorus (P), potassium (K) nutrients on the growth, photosynthetic characteristics and yield in three-year old saplings of C. arabica with the density of 4500 individuals per hectare were measured. In general, N is the most important factor influencing the growth, photosynthetic capacity and yield of C. arabica, followed by K and P, respectively. The yield can be improved through spraying appropriate amount of trace elements in the leaves. The optimum matching experiments in fertilization level of N:P2O5: K2O is at the ratio of 1:0.5:1. The high yield of C. arabica need high nutrient demands, but the optimum amount of fertilizer of N, P2O5, K2O is 100, 50, 100 g per individual according to the cost-benefits analysis. The yield of C. arabica was closely related with the numbers of branch, total leaf areas and maximum rate of net photosynthesis (Amax) among different treatments. Different fertilization strategy had no significantly effects on the photochemical efficiency in dawn, but all indicators showed that the higher-fertilized plants could significantly alleviate diurnal photoinhibitio
Energy efficiency analysis of marine high-powered medium-speed diesel engine base on energy balance and exergy
High-powered, medium-speed diesel engines are widely used in merchant ships. Improving energy efficiency by using energy rationally is critical to reducing both environmental pollution and transport charges. In this paper, the energy efficiency of marine high-powered, medium-speed diesel engine is investigated. A new thermal cycle model of the marine engine is developed using AVL-Boost software. The thermodynamic data of the engine thermal cycle are obtained from the AVL-Boost software. The energy efficiency of the marine diesel engine is evaluated using both energy balance and exergy analysis. From the energy balance analysis, about 25% of the total energy is lost through exhaust heat. This forms the largest energy loss. However, using exergy analysis the largest energy loss originates from the irreversible exergy loss produced during the combustion process. This represents about 36% of the total energy loss. To explore ways to reduce energy loss and improve the energy efficiency, the effects of critical combustion parameters in the thermal cycle (combustion quality index, combustion starting angle and combustion duration angle) on energy distributions are discussed. The decrease in the combustion quality index, combustion starting angle and combustion duration angle (within a reasonable range) all contribute to reduce the total energy loss, increasing the indicated work and improving energy efficiency.Zhi-Min Yao, Zuo-Qin Qian, Rong Li, Eric H
Influence of design parameters on inductances of e-core axial field flux-switching permanent magnet machines
Serum exosomal miR-122-5p is a new biomarker for both acute coronary syndrome and underlying coronary artery stenosis
Plio-Pleistocene vegetation changes in the North China Plain: Magnetostratigraphy, oxygen and carbon isotopic composition of pedogenic carbonates
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