125 research outputs found
Problem of Statistical Model in Deep Inelastic Scattering Phenomenology
Recent Deep Inelastic data leads to an up-down quark asymmetry of the nucleon
sea. Explanations of the flavour asymmetry and the di-lepton production in
proton-nucleus collisions call for a temperature MeV in a
statistical model. This T may be conjectured as being due to the
Fulling-Davies-Unruh effect. But it is not possible to fit the structure
function itself.Comment: 8 pages, 2 figures, figures on request to [email protected],
IFT preprint-IFT P-050/93, Late
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. 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 deduced with built in AF and CSR. In some
other stars broad absorption bands 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_sun 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 1E1207-5209 which is again suggestive of
SS.Comment: 5 pages, 4 figures, accepted for publication in the MNRA
Scaling Law for Baryon Coupling to its Current and its possible applications
The baryon- coupling to its current (), in conventional QCD sum
rule calculations (QCDSR), is shown to scale as the cubic power of the baryon
mass, . Some theoretical justification for it comes from a simple
light-cone model and also general scaling arguments for QCD. But more
importantly, taken as a phenomenological ansatz for the present, this may find
very good use in current explorations of possible applications of QCDSR to
baryon physics both at temperature , and/or density , .Comment: 10 pages, 2 figures, 1 tex picture and 1 ps pictur
Superburst: surface phenomenon of compact objects
We suggest that superbursts from some low mass X-ray binaries may be due to
breaking and re-formation of diquark pairs, on the surface of realistic strange
stars. Diquarks are expected to break up due to the explosion and shock of the
thermonuclear process. The subsequent production of copious diquark pairing may
produce sufficient energy to produce the superbursts.Comment: 4 pages; to appear in the Proceedings of COSPAR Colloquium "Spectra &
Timing of Compact X-ray Binaries," January 17-20, 2005, Mumbai, Indi
Density dependent strong coupling constant of QCD derived from compact star data
The present work is an endeavour to connect the properties of tiny nearly
massless objects with those of some of the most massive ones, the compact
stars.
Since 1996 there is major influx of X-ray and ray data from binary
stars, one or both of which are compact objects that are difficult to explain
as neutron stars since they contain a mass M in too small a radius R . The
suggestion has been put forward that these are strange quark stars (SS)
explainable in a simple model with chiral symmetry restoration (CSR) for the
quarks and the M, R and other properties like QPOs (quasi periodic
oscillations) in their X-ray power spectrum.
It would be nice if this astrophysical data could shed some light on
fundamental properties of quarks obeying QCD. One can relate the strong
coupling constant of QCD, to the quark mass through the
Dyson-Schwinger gap equation using the real time formalism of Dolan and Jackiw.
This enables us to obtain the density dependence of from the simple
CSR referred to above. This way fundamental physics, difficult to extract from
other models like for example lattice QCD, can be constrained from present-day
compact star data and may be put back to modelling the dense quark phase of
early universe.Comment: 7 pages, 4 figure
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