120924061
IS THERE A SPIN 1/2 WEAK DOUBLET OF SKYRMIONS ALMOST DEGENERATE WITH W AND Z?
118656436
A COMPARISON OF CHIRAL MODELS WITH AND WITHOUT FUNDAMENTAL MESON FIELDS AND THE POSSIBILITY OF DEFORMED MEAN FIELD SOLUTIONS
121478460
On the density dependence of nucleon size in nuclear medium
Abstract There has been speculation regarding the increase in nucleon size in dense nuclear medium. Following recent suggestions this increase with the restoration of chiral symmetry at high density is estimated. A measure of symmetry breaking is the pion decay constant, ƒ π and its density dependence is extractedfrom QCD sum rules. The nucleon size is inversely proportional to ƒ π .
119479067
Rotational bands in the baryon spectrum. II
A nonrelativistic constituent quark model is developed for baryons where the quarks are moving in a deformable mean field. The deformation parameters in each state are determined by minimization of the energy, subject to the constraint of volume conservation in the state. It is found that while the ground state is spherical, the excited-state configurations are deformed. The deformation increases with excitation energy. This is responsible for the observed low-lying states N(1440)1/2/sup +/ and ..delta..(1900)1/2/sup -/. The experimental states are grouped in rotational bands, and the deduced moment-of-inertia parameter is shown to be consistent with the quantum-mechanical calculation. A detailed comparison with experimental data is made.
15882822
Entropy & viscosity bound of strange stars
At finite temperature (T) there is a link with general relativity and hydrodynamics that leads to a lower bound for the ratio of shear viscosity and entropy density (\eta/s). We find that the bound is saturated in the simple model for quark matter that we use for strange stars at T = 80 MeV, at the surface of a strange star. At this T we have the possibility of cosmic separation of phases. We find that, although strongly correlated, the quark matter at the surface of strange stars constitute the most perfect interacting fluid permitted by nature. At the centre of the star, however, the density is higher and conditions are more like the results found for perturbative QCD.
119382272
Is SAX J1808.4-3658 a strange star?
The possibility of strange stars is one of the most important issues in the study of compact objects. Here we use the observations of the newly discovered millisecond x-ray pulsar SAX J1808.4-3658 to constrain the radius of the compact star. Comparing the mass-radius relation of SAX J1808.4-3658 with theoretical models for both neutron stars and strange stars, we argue that a strange star model could be more consistent with SAX J1808.4-3658, and suggest that it is a likely strange star candidate. Our results are useful in constraining microscopic chiral symmetry restoration parameters in the quantum chromodynamics (QCD) modeling of strange matter.
111241112
Linearization of the Fermilab recycler high level RF
In studying the recycler high level RF, it was found that at 89 kHz, the lowest frequency required by the system, some nonlinearities in magnitude and phase were discovered. The visible evidence of this was that beam injected in a barrier bucket had a definite slope at the top. Using a network analyzer, the S-parameter S/sub 21/ was realized for the overall system and from mathematical modeling a second order numerator and denominator transfer function was found. The inverse of this transfer function gives our linearization transfer function. The linearization transfer function was realized in hardware by summing a high pass, band pass and low pass filter together. The resulting magnitude and phase plots, along with actual beam response will be shown.
122069162
Design and operation of PET radio frequency quadrupoles
The PET isotope production accelerator built by a collaboration of BRF, FNAL, SAIC, and UW consists of four RFQ's to accelerate /sup 3/He/sup 2+/ ions to 10.5 MeV for production of radioactive /sup 18/F, /sup 11/C, /sup 15/O and /sup 13/N isotopes. The design, tuning, and operational results are presented.