60,196 research outputs found
Oxygen complexes formed at 4 K
Storage stability of oxygen complexes at 4
Electronic visualization of gas bearing behavior
Visualization technique produces a visual simulation of gas bearing operation by electronically combining the outputs from the clearance probes used to monitor bearing component motion. Computerized recordings of the probes output are processed, displayed on an oscilloscope screen and recorded with a high-speed motion picture camera
Does HBT Measure the Freeze-out Source Distribution?
It is generally assumed that as a result of multiple scattering, the source
distribution measured in HBT interferometry corresponds to a chaotic source at
freeze-out. This assumption is subject to question as effects of multiple
scattering in HBT measurements must be investigated within a quantum-mechanical
framework. Applying the Glauber multiple scattering theory at high energies and
the optical model at lower energies, we find that multiple scattering leads to
an effective HBT density distribution that depends on the initial chaotic
source distribution with an absorption.Comment: 4 pages, talk presented at QM2004 Conference, January 11-17, 2004,
Oakland, California, USA, to be published in the Proceeding
Analysis and computer programs to calculate acoustic wave properties of baffled chambers
Analytical methods and four computer programs have been developed for calculating wave motion in closed, baffled chambers with rigid and non-rigid boundaries. Application of these methods to design of injector-face baffles in liquid propellant engines will provide significant insight into effects of baffles on combustion stability
Spin-Seebeck effect in a strongly interacting Fermi gas
We study the spin-Seebeck effect in a strongly interacting, two-component
Fermi gas and propose an experiment to measure this effect by relatively
displacing spin up and spin down atomic clouds in a trap using spin-dependent
temperature gradients. We compute the spin-Seebeck coefficient and related
spin-heat transport coefficients as functions of temperature and interaction
strength. We find that when the inter-spin scattering length becomes larger
than the Fermi wavelength, the spin-Seebeck coefficient changes sign as a
function of temperature, and hence so does the direction of the
spin-separation. We compute this zero-crossing temperature as a function of
interaction strength and in particular in the unitary limit for the inter-spin
scattering
Azimuthal Asymmetry of Direct Photons in High Energy Nuclear Collisions
We show that a sizeable azimuthal asymmetry, characterized by a coefficient
v_2, is to be expected for direct photons produced in non-central high energy
nuclear collisions. This signal is generated by photons radiated by jets
interacting with the surrounding hot plasma. The anisotropy is out of phase by
an angle with respect to that associated with the elliptic anisotropy
of hadrons, leading to negative values of v_2. Such an asymmetry, if observed,
could be a signature for the presence of a quark gluon plasma and would
establish the importance of jet-plasma interactions as a source of
electromagnetic radiation.Comment: New title. Final versio
Dissociation rates of J/psi's with comoving mesons - thermal vs. nonequilibrium scenario
We study J/psi dissociation processes in hadronic environments. The validity
of a thermal meson gas ansatz is tested by confronting it with an alternative,
nonequilibrium scenario. Heavy ion collisions are simulated in the framework of
the microscopic transport model UrQMD, taking into account the production of
charmonium states through hard parton-parton interactions and subsequent
rescattering with hadrons. The thermal gas and microscopic transport scenarios
are shown to be very dissimilar. Estimates of J/psi survival probabilities
based on thermal models of comover interactions in heavy ion collisions are
therefore not reliable.Comment: 12 pages, 6 figure
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