487 research outputs found
Quark and gluon distributions at the earliest stage of heavy ion collision
Using the general framework of quantum field kinetics we consider new
principles to compute initial distribution of quarks and gluons after the first
hard interaction of heavy ions. We start by rewriting the integral equations of
QCD in the form which is generalizations of the familiar QCD evolution
equations. These equations describe both space-time-- and --evolution
before the collision, and allow one to use the DIS data without reference
to parton phenomenology. New technique generate perturbation theory that avoid
double count of the processes, does not contain an artificial factorization
scale, and does not require low-momentum cut-offs since infrared behavior is
controlled by the DIS data.Comment: 30 pages, REVTeX, 5 postscript figures appende
Low-mass dileptons from nonequilibrium QGP
The rate of the emission of the high energy low-mass dileptons from the QGP
is found in the first nonvanishing order with respect to strong coupling. We
base on the real-time kinetic approach [2] without an explicit assumption about
a complete thermal equilibrium in the emitting system. For the class of the
partons distributions which may simulate that of the "hot glue scenario"[1] the
rate of emission is found analytically .
( Figures can be obtained from the author )Comment: 7 pages, Preprint SUNY-NTG-93-2
Scenario for Ultrarelativistic Nuclear Collisions: V. Onset of Deconfinement. (How the Nuclei Get Unbound.)
We consider a Euclidean extension of the wedge form of Hamiltonian dynamics,
which explicitly accounts for the strong localization of the first interaction
in nuclear collisions. A new principle of the analytic continuation via the
tetrad vector is introduced. We discover the existence of self-dual solutions
with short life-times (ephemerons) and conjecture that these vacuum
fluctuations can lower the Euclidean action of the system of the colliding
nuclei, thus enforcing a breakdown of the nuclei coherence. We suggest that the
ephemerons can be identified with the gluons-partons, which are resolved in
high-energy nuclear collisions.Comment: 19 pages, RevTe
The wedge form of relativistic dynamics
It is commonly accepted that in hadronic or nuclear collisions at extremely
high energies the shortest scales are explored. At the classical level, this
property of the interaction is closely related to the Lorentz contraction of
the fields of colliding particles which provides instantaneous switching the
interaction on. I argue that the underlying quantum dynamics should be confined
to within the light wedge of the two-dimensional plane where the first
interaction takes place and suggest to include this property as the boundary
condition for the quantum field theory which describes the collision process.
Connection between the type of inclusive process and the temporal order of its
dynamical evolution is discussed. The one-particle states and propagators of
the perturbation theory for the scalar and fermion fields are found.Comment: 14 pages, REVTe
Heavy dileptons from nonequilibrium QGP
The rate of emission of heavy dileptons from QGP is found without an
assumption of its complete thermal equilibrium. We base on the real-time
quantum field kinetic approach [1] and use the expansion up to the second order
with respect to strong coupling constant . The final answer is not free from
the collinear singularities and we show that this is the actual issue. As a
result the main contribution to the rate of the heavy dileptons production at
comes from the process .
( Figures can be obtained from the author )Comment: 20 pages, Preprint SUNY-NTG-93-2
Scenario for Ultrarelativistic Nuclear Collisions: III. Gluons in the expanding geometry
We derive expressions for various correlators of the gauge field and find the
propagators in Hamiltonian dynamics which employs a new gauge . This
gauge is a part of the wedge form of relativistic dynamics suggested earlier as
a tool for the study of quantum dynamics in ultra-relativistic heavy ion
collisions. We prove that the gauge is completely fixed. The gauge field is
quantized and the field of radiation and the longitudinal fields are
unambiguously separated. The new gauge puts the quark and gluon fields of the
colliding hadrons in one Hilbert space and thus allows one to avoid
factorization.Comment: 25 pages, RevTe
Transient topological objects in high energy collisions
The possible topology of quantum fluctuations which take place at the
earliest stage of high-energy processes is studied. A new exact solution of
Yang-Mills equations with fractional topological charge and carrying a single
color is found.Comment: 4 pages, RevTe
Spurious poles of the axial gauge propagators and dynamics of the interacting fields
The origin of the spurious poles of the gauge field propagators in the
temporal axial and the null-plane gauges is discussed. The conclusion is that
these poles do not require any special prescription. They are a manifestation
of the fact that that the gauge field acquires a static configuration.Comment: 10 pages, REVTe
Real photons from nonequilibrium QGP
We calculate the rate of the emission of the photons from the QGP. We base on
the real-time kinetic approach [1] without an explicit assumption about a
complete thermal equilibrium in the emitting system.
( Figures can be obtained from the author )Comment: 9 pages, Preprint SUNY-NTG-93-1
Scenario for Ultrarelativistic Nuclear Collisions: IV. Effective quark mass at the early stage
Using the framework of wedge dynamics, we compute the effective transverse
mass of a soft quark mode propagating in the expanding background of hard
quarks and gluons created at the earliest time of the collision. We discover
that the wedge dynamics does not require any external infrared or collinear
cut-off. The effective mass is produced mainly due to the forward quark-quark
scattering mediated by the longitudinal (in sense of Gauss' law) magnetic
fields. Contribution of the radiation field is parametrically suppressed.Comment: 25 pages, 6 psfigures, RevTe
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