81,359 research outputs found
Suppression of the high charged hadron at the LHC
We present a parameter free postdiction of the high- charged-hadron
nuclear modification factor () in two centralities, measured by the CMS
collaboration in - collisions at the Large Hadron Collider (LHC). The
evolution of the bulk medium is modeled using viscous fluid dynamics, with
parameters adjusted to describe the soft hadron yields and elliptic flow.
Assuming the dominance of radiative energy loss, we compute the medium
modification of the using a perturbative QCD based formalism, the
higher twist scheme. The transverse momentum diffusion coefficient is
assumed to scale with the entropy density and normalized by fitting the
in the most central - collisions at the Relativistic Heavy-Ion
Collider (RHIC). This set up is validated in non-central - collisions
at RHIC and then extrapolated to - collisions at the LHC, keeping the
relation between and entropy density unchanged. We obtain a
satisfactory description of the CMS over the range from 10-100
GeV.Comment: 4 pages, 3 figures, revtex4, new experimental data used, new
calculations with systematic error bands, changed abstract and contents,
conclusions unchange
A silicone column for GC analysis of polar and nonpolar chemicals
The investigation of the Saturnian System is being proposed jointly by NASA and the European Space Agency (ESA). The mission is scheduled for a launch in 1996. The mission provides an opportunity for close observation and exploration of Saturn's atmosphere, the complex Saturnian System of satellites and rings, Titan (Saturn's planet-sized moon), and Saturn's magnetosphere. The mission gives special attention to Titan which is blanketed by a thick, opaque atmosphere. An atmospheric probe will be deposited into the Titan Atmosphere for in situ measurement during a slow, three hour descent to the surface. The results from this analysis may provide the information which is important to the research of chemical evolution, and the origin of life. An analytical system was developed as a part of the Titan Aerosol Gas Experiment (TAGEX), a proposed experiment for the Cassini Mission. This system will use two highly sensitive detectors, the Metastable Ionization Detector (MID) and the Ion Mobility Spectrometer (IMS). Unfortunately, when commercial columns are utilized with these highly sensitive detectors, volatile components continuously bleed from the column and interfere with the detector. In addition, light columns must be able to separate polar and nonpolar organic chemicals within 10-15 minutes under isothermal conditions for the Titan Mission. Therefore, a highly crosslinked silicone polymeric packed column was developed which is able to efficiently separate amines, alcohols, and hydrocarbons with retention times less that 15 minutes at 100 C isothermal condition
A Comparison Between the Variational Solution and the Experimental Data
Current distribution on dipole antenna with nonreflecting resistive loading, expressed using variation metho
An experimental study of imperfectly conducting dipoles
Input admittances of imperfectly conducting dipole antennas measured in ultrahigh frequency rang
Wireless Broadcast with Physical-Layer Network Coding
This work investigates the maximum broadcast throughput and its achievability
in multi-hop wireless networks with half-duplex node constraint. We allow the
use of physical-layer network coding (PNC). Although the use of PNC for unicast
has been extensively studied, there has been little prior work on PNC for
broadcast. Our specific results are as follows: 1) For single-source broadcast,
the theoretical throughput upper bound is n/(n+1), where n is the "min
vertex-cut" size of the network. 2) In general, the throughput upper bound is
not always achievable. 3) For grid and many other networks, the throughput
upper bound n/(n+1) is achievable. Our work can be considered as an attempt to
understand the relationship between max-flow and min-cut in half-duplex
broadcast networks with cycles (there has been prior work on networks with
cycles, but not half-duplex broadcast networks).Comment: 23 pages, 18 figures, 6 table
The diversity of quasars unified by accretion and orientation
Quasars are rapidly accreting supermassive black holes at the center of
massive galaxies. They display a broad range of properties across all
wavelengths, reflecting the diversity in the physical conditions of the regions
close to the central engine. These properties, however, are not random, but
form well-defined trends. The dominant trend is known as Eigenvector 1, where
many properties correlate with the strength of optical iron and [OIII]
emission. The main physical driver of Eigenvector 1 has long been suspected to
be the quasar luminosity normalized by the mass of the hole (the Eddington
ratio), an important quantity of the black hole accretion process. But a
definitive proof has been missing. Here we report an analysis of archival data
that reveals that Eddington ratio indeed drives Eigenvector 1. We also find
that orientation plays a significant role in determining the observed
kinematics of the gas, implying a flattened, disklike geometry for the
fast-moving clouds close to the hole. Our results show that most of the
diversity of quasar phenomenology can be unified with two simple quantities,
Eddington ratio and orientation.Comment: This is the author's version of the work; 18 pages including
Supplementary Information; to appear in the 11 September 2014 issue of Nature
at http://dx.doi.org/10.1038/nature1371
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