52,092 research outputs found
Tomographic Studies of the sQGP
Azimuthal correlation functions are used to study jet- and di-jet properties
as a function of centrality in Au+Au collisions at =200
GeV. Utilizing a novel technique to decompose the correlation function into a
(di-)jet and an underlying event, the jet-pair distribution is extracted and
compared to similar results for d+Au collisions obtained at the same collision
energy. A striking similarity is observed between the widths and associated
yields of the (di-)jet distributions for d+Au and peripheral Au+Au collisions.
By contrast, the distributions for mid-central Au+Au collisions indicate an
increase in the di-jet yield with centrality, and a very broad away-side jet
having a possible minimum at . These features point to
significant medium induced modification to the away-side jet and are compatible
with recent predictions of jet-induced "conical flow".Comment: Proc. 21st. Winter Workshop on Nuclear Dynamic
From meson-nucleon scattering to vector mesons in nuclear matter
We employ meson-nucleon scattering data to deduce the properties of the
low-mass vector mesons in nuclear matter, and present results for the
and in-medium spectral functions. The corresponding thermal emission
rate for lepton pairs is also discussed.Comment: Talk given at 28th International Workshop on Gross Properties of
Nuclei and Nuclear Excitations, Hirschegg, Austria, 16-22 Jan. 200
The spontaneous and induced synthesis of Epstein-Barr virus antigens in Raji cells immobilized on surface coated with anti-lymphocyte globulin
Immobilization of Raji cells on surface coated with anti-lymphocyte globulin (ALG) at low cell densities lead to the synthesis of Epstein-Barr virus (EBV) early antigen (EA) in up to 5% of the cells. At higher cell densities the percentage of antigen-positive cells decreased and at confluency no antigen synthesis was observed. Addition of iododeoxyuridine (IdUrd) to low density cultures increased the expression of EA to 20%, whereas in confluent cultures the cells could not be induced to synthesize EA. Treatment of cells in suspension with ALG failed to induced EA synthesis and did not potentiate the effect of IdUrd. Immobilized Raji cells proved to be suitable targets for superinfection with EBV derived from P3HR1 cultures
Electronic Excitations and Correlation Effects in Metals
Theoretical descriptions of the spectrum of electronic excitations in real
metals have not yet reached a fully predictive, "first-principles" stage. In
this paper we begin by presenting brief highlights of recent progress made in
the evaluation of dynamical electronic response in metals. A comparison between
calculated and measured spectra - we use the loss spectra of Al and Cs as test
cases - leads us to the conclusion that, even in "weakly-correlated" metals,
correlation effects beyond mean-field theory play an important role.
Furthermore, the effects of the underlying band structure turn out to be
significant. Calculations which incorporate the effects of both dynamical
correlations and band structure from first principles are not yet available. As
a first step towards such goal, we outline a numerical algorithm for the
self-consistent solution of the Dyson equation for the one-particle Green's
function. The self-energy is evaluated within the shielded-interaction
approximation of Baym and Kadanoff. Our method, which is fully conserving, is a
finite-temperature scheme which determines the Green's function and the
self-energy at the Matsubara frequencies on the imaginary axis. The analytical
continuation to real frequencies is performed via Pade approximants. We present
results for the homogeneous electron gas which exemplify the importance of
many-body self-consistency.Comment: 32 pages, 6 figures; "Fifty Years of the Correlation Problem",
invited paper, to be published in Mol.Phy
The regulated expression of Epstein-Barr virus. III. Proteins specified by EBV during the lytic cycle
The experiments show that 30 virus-induced or virus-specified proteins were synthesized in Raji cells after superinfection with Epstein-Barr virus (EBV) derived from P3HR1 cells. Using a combination of pulse labelling, application of cycloheximide blocks at different times post-infection, treatment with amino acid analogues and inhibition of DNA synthesis it was shown that three groups of proteins appear in Raji cells after superinfection; the synthesis of the proteins in any one group appears to be coordinately regulated. Amongst the six virus-induced proteins which were synthesized immediately after release from an early cycloheximide block one would expect to find those proteins essential for the transition from EBNA to EA synthesis. Using human sera with differing specificities for the various antigen groups 11 proteins were identified as being specifically precipitated by sera having high titres against the EBV-induced early antigen complex
Measuring the Decorrelation Times of Fourier Modes in Simulations
We describe a method to study the rate at which modes decorrelate in
numerical simulations. We study the XY model updated with the Metropolis and
Wolff dynamics respectively and compute the rate at which each eigenvector of
the dynamics decorrelates. Our method allows us to identify the decorrelation
time for each mode separately. We find that the autocorrelation function of the
various modes is markedly different for the `local' Metropolis compared to the
`non-local' Wolff dynamics. Equipped with this new insight, it may be possible
to devise highly efficient algorithms.Comment: 16 pp (LaTeX), PUPT-1378 , IASSNS-HEP-93/
- …