8,751 research outputs found
Experimental L-band SST satellite communications/surveillance terminal study. Volume 5 - Aircraft terminal definition
Aircraft terminal designs for experimental and operational supersonic transport for L band satellite air traffic contro
SSME structural dynamic model development
A mathematical model of the Space Shuttle Main Engine (SSME) as a complete assembly, with detailed emphasis on LOX and High Fuel Turbopumps is developed. The advantages of both complete engine dynamics, and high fidelity modeling are incorporated. Development of this model, some results, and projected applications are discussed
Energies of B_s meson excited states - a lattice study
This is a follow-up to our earlier work on the energies and radial
distributions of heavy-light mesons. The heavy quark is taken to be static
(infinitely heavy) and the light quark has a mass about that of the strange
quark. We now concentrate on the energies of the excited states with higher
angular momentum and with a radial node. A new improvement is the use of
hypercubic blocking in the time direction.
The calculation is carried out with dynamical fermions on a 16 cubed times 32
lattice with a lattice spacing approximately 0.1 fm generated using a
non-perturbatively improved clover action.
In nature the closest equivalent of this heavy-light system is the B_s meson,
which allows us to compare our lattice calculations to experimental results
(where available) or to give a prediction where the excited states,
particularly P-wave states, should lie. We pay special attention to the
spin-orbit splitting, to see which one of the states (for a given angular
momentum L) has the lower energy. An attempt is made to understand these
results in terms of the Dirac equation.Comment: 35 pages. v3: Data from two new lattices added. New results in
several chapter
The Iliad’s big swoon: a case of innovation within the epic tradition
In book 5 of the Iliad Sarpedon suffers so greatly from a wound that his ‘‘ψυχή leaves him’. Rather than dying, however, Sarpedon lives to fight another day. This paper investigates the phrase τὸν δὲ λίπε ψυχή in extant archaic Greek poetry to gain a sense of its traditional referentiality and better assess the meaning of Sarpedon’s swoon. Finding that all other instances of the ψυχή leaving the body signify death, it suggests that the Iliad exploits a traditional unit of utterance to flag up the importance of Sarpedon to this version of the Troy story
The heavy quark's self energy from moving NRQCD on the lattice
We present a calculation of the heavy quark's self energy in moving NRQCD to
one-loop in perturbation theory. Results for the energy shift and external
momentum renormalisation are discussed and compared with non-perturbative
results. We show that the momentum renormalisation is small, which is the
result of a remnant of re-parameterisation invariance on the lattice.Comment: Talk given at Lattice2004(heavy), Fermilab, June 21-26, 200
Dipolar and scalar He and Xe frequency shifts in mm-sized cells
We describe a He-Xe comagnetometer operating in stemless
anodically bonded cells with a 6 mm volume and a Xe spin coherence
time of 300 sec. We use a Rb pulse-train magnetometer with co-linear
pump and probe beams to study the nuclear spin frequency shifts caused by spin
polarization of He. By systematically varying the cell geometry in a
batch cell fabrication process we can separately measure the cell shape
dependent and independent frequency shifts. We find that a certain aspect ratio
of the cylindrical cell can cancel the effects of He magnetization that
limit the stability of vapor-cell comagnetometers. Using this control we also
observe for the first time a scalar He-Xe collisional frequency
shift characterized by an enhancement factor .Comment: 4 pages, 4 figure
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