16,988 research outputs found
On the temperature dependence of correlation functions in the space like direction in hot QCD
We study the temperature dependence of quark antiquark correlations in the
space like direction. In particular, we predict the temperature dependence of
space like Bethe-Salpeter amplitudes using recent Lattice gauge data for the
space like string potential. We also investigate the effect of the space like
string potential on the screening mass and discuss possible corrections which
may arise when working with point sources.Comment: 15 pages 8 figures (not included, will be sent on request),
(SUNY-NTG-94-3
The chemical equilibration volume: measuring the degree of thermalization
We address the issue of the degree of equilibrium achieved in a high energy
heavy-ion collision. Specifically, we explore the consequences of incomplete
strangeness chemical equilibrium. This is achieved over a volume V of the order
of the strangeness correlation length and is assumed to be smaller than the
freeze-out volume. Probability distributions of strange hadrons emanating from
the system are computed for varying sizes of V and simple experimental
observables based on these are proposed. Measurements of such observables may
be used to estimate V and as a result the degree of strangeness chemical
equilibration achieved. This sets a lower bound on the degree of kinetic
equilibrium. We also point out that a determination of two-body correlations or
second moments of the distributions are not sufficient for this estimation.Comment: 16 pages, 15 figures, revtex
Deciphering Deconfinement in Correlations of Conserved Charges
Diagonal and off-diagonal flavor and conserved charge susceptibilities reveal
the prevalent degrees of freedom of heated strongly interacting matter. Results
obtained from lattice simulations are compared with various model estimates in
an effort to weed down various possible pictures of a quark gluon plasma. We
argue that the vanishing of the off-diagonal quark flavor susceptibilities and
its derivatives with respect to chemical potential, at temperatures above
1.5Tc, can only be understood in a picture of a gas or liquid composed of
quasi-particles which carry the same quantum numbers as quarks and antiquarks.
A potential new observable, blind to neutral and non-strange particles, is
introduced and related via isospin symmetry to the ratio of susceptibilities of
baryonic strangeness to strangeness generated in the excited matter created at
RHIC.Comment: 5 pages, 3 figures, LATEX, To appear in the proceedings of the
International Conference on Strangeness in Quark Matter, Los Angeles, CA, Mar
26-31, 200
The Goldberger-Miyazawa-Oehme sum rule revisited
The Goldberger-Miyazawa-Oehme sum rule is used to extract the pion-nucleon
coupling constant from experimental N information. Chiral perturbation
theory is exploited in relating the pionic hydrogen s-wave level shift and
width results to the appropriate scattering lengths. The deduced value for the
coupling is , where the largest source of uncertainty is
the determination of the s-wave scattering length from the atomic
level shift measurement.Comment: 4 pages, 1 figure. v2: Revised the second last paragraph of 5th
section and clarified the electromagnetic corrections (Tromborg vs.
PT). Also removed the KH80 slope from the fig.
Measures of Charge Fluctuations in Nuclear Collisions
The properties of two measures of charge fluctuations D and Delta Phi_q are
discussed within several toy models of nuclear collisions. In particular their
dependence on mean particle multiplicity, multiplicity fluctuations and net
electric charge are studied. It is shown that the measure Delta Phi_q is less
sensitive to these trivial biasing effects than the originally proposed measure
D. Furthermore the influence of resonance decay kinematics is analysed and it
is shown that it is likely to shadow a possible reduction of fluctuations due
to QGP creation.Comment: 9 pages, 9 figure
Extended Gibbs ensembles with flow
A statistical treatment of finite unbound systems in the presence of
collective motions is presented and applied to a classical Lennard-Jones
Hamiltonian, numerically simulated through molecular dynamics. In the ideal gas
limit, the flow dynamics can be exactly re-casted into effective time-dependent
Lagrange parameters acting on a standard Gibbs ensemble with an extra total
energy conservation constraint. Using this same ansatz for the low density
freeze-out configurations of an interacting expanding system, we show that the
presence of flow can have a sizeable effect on the microstate distribution.Comment: 7 pages, 4 figure
Surprisingly Simple Spectra
The large N limit of the anomalous dimensions of operators in
super Yang-Mills theory described by restricted Schur polynomials, are studied.
We focus on operators labeled by Young diagrams that have two columns (both
long) so that the classical dimension of these operators is O(N). At large N
these two column operators mix with each other but are decoupled from operators
with columns. The planar approximation does not capture the large N
dynamics. For operators built with 2, 3 or 4 impurities the dilatation operator
is explicitly evaluated. In all three cases, in a certain limit, the dilatation
operator is a lattice version of a second derivative, with the lattice emerging
from the Young diagram itself. The one loop dilatation operator is diagonalized
numerically. All eigenvalues are an integer multiple of and there
are interesting degeneracies in the spectrum. The spectrum we obtain for the
one loop anomalous dimension operator is reproduced by a collection of harmonic
oscillators. This equivalence to harmonic oscillators generalizes giant
graviton results known for the BPS sector and further implies that the
Hamiltonian defined by the one loop large dilatation operator is
integrable. This is an example of an integrable dilatation operator, obtained
by summing both planar and non-planar diagrams.Comment: 34 page
Nonplanar integrability at two loops
In this article we compute the action of the two loop dilatation operator on
restricted Schur polynomials that belong to the su(2) sector, in the displaced
corners approximation. In this non-planar large N limit, operators that
diagonalize the one loop dilatation operator are not corrected at two loops.
The resulting spectrum of anomalous dimensions is related to a set of decoupled
harmonic oscillators, indicating integrability in this sector of the theory at
two loops. The anomalous dimensions are a non-trivial function of the 't Hooft
coupling, with a spectrum that is continuous and starting at zero at large N,
but discrete at finite N.Comment: version to appear in JHE
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