52,534 research outputs found
QCD color interactions between two quarks
We study the QCD color interactions between static two heavy quarks at zero
temperature in a quenched SU(3) lattice gauge simulation: in addition to the
standard singlet potentials, we calculate octet
potentials, symmetric and antisymmetric potentials. It is shown that the
antisymmetric channel behaves as a linearly rising potential at large
quark separations. We further find that the octet and symmetric
channels have the complex dependence on the distance; at short distances they
are repulsive forces, while at large distances, they show linearly rising
feature. Ratio of string tensions between singlet and
antisymmetric potentials is described in terms of the Casimir factor
Gluon Propagators and Confinement
We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at
beta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16
(deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to
avoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon
propagators show quite different behavior from those of massless gauge fields:
(1) In the confinement phase, G(t) shows massless behavior at small and large
t, while around 5<t<15 it behaves as massive particle, and (2) effective mass
observed in G(z) becomes larger as z increases. (3) In the deconfinement phase,
G(z) shows also massive behavior but effective mass is less than in the
confinement case. In all cases, slope masses are increasing functions of t or
z, which can not be understood as addtional physical poles.Comment: 6 pages in Postscrip
Exotic Properties of Light Nuclei and their Neutron Capture Cross Sections
We have investigated the implications of the neutron halo configuration,
observed in the ground-state of some neutron-rich light nuclei, on neutron
radiative transition processes. In particular, we have studied the influence of
the neutron halo on the direct radiative capture (DRC) process. The energy
dependence as well as the strength of E1 emission due to incident p-wave
neutrons is strongly influenced by the halo configuration of the residual
nucleus capturing state. We have compared the calculated 10Be(n,gamma)11Be DRC
cross section with that derived from the experiment in the inverse kinematics
(Coulomb dissociation of 11Be). We show from the comparison that some important
information on the structure of the halo nucleus 11Be can be derived.Comment: Contribution to the 4th International Seminar on Interaction of
Neutrons with Nuclei, Dubna (Russia), April 199
Transport Coefficients of Quark Gluon Plasma From Lattice Gauge Theory
Numerical results for the transport coefficients of quark gluon plasma are
obtained by lattice simulations on on lattice with the quench
approximation where we apply the gauge action proposed by Iwasaki. The bulk
viscosity is consistent with zero, and the shear viscosity is slightly smaller
than the typical hadron masses. They are not far from the simple extrapolation
on the figure of perturbative calculation in high temperature limit down to . The gluon propagator in the confined and deconfined phases are
also discussed.Comment: Quark Matter 97(talk at parallel session QCD) 4 pages in latex, 4
Postscript figure
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