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.
13958309
Evidence for strange stars from joint observation of harmonic absorption bands and of redshift
From recent reports on terrestrial heavy ion collision experiments it appears that one may not obtain information about the existence of asymptotic freedom (AF) and chiral symmetry restoration (CSR) for quarks of QCD at high density. This information may still be obtained from compact stars – if they are made up of strange quark matter (SQM). 
 
 
 
Very high gravitational redshift lines (GRL), seen from some compact stars, seem to suggest high ratios of mass and radius (M/R) for them. This is suggestive of strange stars (SS) and can in fact be fitted very well with SQM equation of state (EOS) deduced with built in AF and CSR. In some other stars broad absorption bands (BAB) appear at about ∼0.3 keV and multiples thereof, that may fit in very well with resonance with harmonic compressional breathing mode frequencies of these SS. Emission at these frequencies are also observed in six stars. 
 
 
 
If these two features of large GRL and BAB were observed together in a single star, it would strengthen the possibility for the existence of SS in nature and would vindicate the current dogma of AF and CSR that we believe in QCD. Recently, in 4U 1700 − 24, both features appear to be detected, which may well be interpreted as observation of SS – although the group that analyzed the data did not observe this possibility. We predict that if the shifted lines, that has been observed, are from neon with GRL shift z= 0.4– then the compact object emitting it is a SS of mass 1.2 M⊙ and radius 7 km. In addition the fit to the spectrum leaves a residual with broad dips at 0.35 keV and multiples thereof, as in 1E 1207 − 5209 which is again suggestive of SS.
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.
2417898
Strange star Equation of State with a modified Richardson potential
Abstract Richardson potential is an phenomenological interquark interaction taking care of two aspects of QCD, namely the asymptotic freedom and the confinement. The original potential has a scale parameter having value ∼400 MeV and is well tested in hadronic property calculations. This potential was then used in strange star calculation. Strange stars are very compact stars composed of strange quark matter, i.e. a very high density strange quark phase consisting of deconfined u , d and s quarks. Here the value of the scale parameter was taken as 100 MeV. The argument was that for a deconfined quark system like a strange star, the scale parameter may have a value quite different from that used in hadronic sector. To remove this discrepancy we introduced two scale parameters in the potential, one for the asymptotic freedom part and the other for the confining part. With suitable values of the parameters, this modified potential has been successfully used in both baryonic property and strange star calculations. The Equation of States obtained with the modified potential are also used to obtain mass–radius relations for the strange stars.
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.
119929273
Decoupling of quark condensate from the effective nucleon mass at high density (ϱ) and temperature (T)
It is found that the quark condensate 〈qq〉, instead of decreasing at high ϱ, as commonly expected, starts to increase after a certain density (∼ 1.5ϱ0 — in standard relativistic nuclear matter models. However, when the models contain coupling constants which are density dependent, 〈qq〉 → 0 at high ϱ and T, and in addition, the effective nucleon mass changes little, showing a decoupling of the mass from the condensate.
109094861
Modification of Linac 7651 driver to operate at 425 MHz
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.