119863535
CHARM AND BEAUTY IN SUM RULES FROM SIMPLE MODELS
There is information (and more will be known) about baryons containing one charm and beauty quark. A simple model of the charm and beauty baryons is found to give results which support the recent findings of other models including the 1/MQ expansion of QCD, where MQ is the heavy quark mass. Sum rules are found from the simple model which can be tested in the near future.
120924061
IS THERE A SPIN 1/2 WEAK DOUBLET OF SKYRMIONS ALMOST DEGENERATE WITH W AND Z?
127351407
Color Singlet Hadron Formation and Phase Transition to Quark - Gluon Plasma in the Bag Model
14202199
Entropy and equation of state for dense hot quark matter and its effect on compact quark stars
Dey et al. [1] derived an equation of state (EOS) for matter in strange stars (SS from hereon) with quark masses showing chiral symmetry restoration (CSM) and an interquark potential which (i) has asymptotic freedom built into it, (ii) shows confinement at zero density (ρB = 0) and deconfinement at high ρB. This EOS gives a stable configuration for chargeless, β-stable quark matter. The SS derived from this EOS fits into the empirical mass -radius (M-R) relations of some stars constraining the CSM parameters [1, 2, 3]. In the present paper we extend the calculation to include high temperatures upto T = 10 MeV ≡ 1.16 × 10 K where the quark gas is still degenerate and find that the empirical M-R relation, derived from astrophysical data, is still satisfied. The EOS is tabulated for T = 10 MeV . The entropy is calculated and matches onto that calculated from hadronic models thus supporting the idea that the quark-hadron transition may be continuous. (1) Dept. of Physics, Presidency College, Calcutta 700 073, India (2) Azad Physics Centre, Dept. of Physics, Maulana Azad College, Calcutta 700 013, India (3) Abdus Salam ICTP, Trieste, Italy (4) Department of Physics, Burdwan University, Burdwan 713104, India. † permanent address; 1/10 Prince Golam Md. Road, Calcutta 700 026, India, e-mail : deyjm@giascl01.vsnl.net.in ** Suported by DST Grant no. SP/S2/K18/96, Govt. of India.
120717106
QCD — MOTIVATED QUARK STARS IN THE LIGHT OF RECENT ASTROPHYSICAL OBSERVATIONS
Are there quark stars in nature? We review the question in the light of modern astrophysical observations. Quark stars have properties which are very similar to those of neutron stars. For example they are now known to have the same kind of cooling properties. Their masses may also be similar. On the other hand, gamma ray bursts (GRB), the brightest phenomenon observable at present in the sky, could possibly be conversion of normal or neutron matter on the surface of a quark star. The best observational evidence for the existence of quark stars seems to be some compact objects, the X-Ray burst source 4U 1820-30, the X-ray pulsar Her X-1, the star 4U 1728-34 and SAX J-1808.4-3658, this last one being the stablest and fastest rotating hard X-ray pulsar known to date. The mass of at least these four objects is high and their radius is low, placing them close to the black hole line, in the mass–radius (M–R) plot.
15993375
Double neutron stars as double strange stars
Double neutron star systems lead to strong tests of general r lativity. The history of the double pulsar PSR J0737−3039 is also very interesting. There are claims that the youn ger member of this binary (pulsar B) had a light progenitor. It is possible that such double pulsar systems are double str ange stars. We suggest that the collapse of the light progeni tor was a phase transition to strange matter and J0737 −3039B is a strange star. This would support small baryon loss implied by the small natal kick velocity for the system J0737 −3039. Using equation of states for strange quark matter and n eutron matter, we have calculated the stellar structure and the baryon conten t of the progenitor as well as the existing star to compare wi th observational predictions. We have also calculated the moment of i ertia using both of the equation of states to facilitate co mparison with expected future measurements. The baryon number of the progenitor turns out to be ∼ 2× 1057 and with small baryon loss the this fits into a strange star of mass 1.25 M⊙. Double neutron stars may be double strange stars. If the mom ent of inertia of these stars are found in the near future as expected, then our predictions can be further tested.
6190198
Narrowband beam loading compensation in the Fermilab Main Injector accelerating cavities
A narrowband beam loading compensation system was installed for the Main Injector accelerating cavities. This feedback operates solely on the fundamental resonant mode of the cavity. This paper describes modifications to the high level radiofrequency system required to make the system operational. These modifications decreased the effect of steady-state beam loading by a factor of 10 and improved the reliability of paraphasing for coalescing.
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.
73632693
Antiproton acceleration in the Fermilab Main Injector using 2.5 MHz (H=28) and 53 MHz (H=588) RF systems
During the Run II era at Fermilab, the Recycler stores antiprotons at 8 GeV and the Main Injector accelerates the antiprotons and the protons from 8 GeV to 150 GeV for Tevatron injection. The Recycler injects antiprotons to the Main Injector in 2.5 MHz rf buckets. This report presents an acceleration scheme for the antiprotons that involves a slow ramp with initial 2.5 MHz acceleration and subsequent fast acceleration with 53 MHz rf system. Beam acceleration and rf manipulation with space charge and beam loading effects are simulated using the longitudinal simulation code ESME. Simulation suggests that one can expect about 15% emittance growth for the entire acceleration cycle with beam loading compensations. Preliminary experimental results with proton beam will also be presented.
55311799
A new flying wire system for the Tevatron
A new flying wire system replaces an older system to enhance the analysis of beam emittance, improve reliability, and support future upgrades to the Tevatron. New VME data acquisition and timing modules allow for more bunches to be sampled more precisely. A LabVIEW application, running on a Macintosh computer, controls the data acquisition and wire motion. The application also analyzes and stores the data as well as handles local and remote commands. The new system flies three wires and fits profiles of 72 bunches to a gaussian function in a total of three seconds. A new console application allows remote operator control and display from any control console. This paper discusses the hardware and software setup, capabilities, and measurement results of the new flying wire system.
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.