36,320 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
Hyperons in nuclear matter
The chiral version of the QMC model, in which the effect of gluon and pion
exchanges is included self-consistently, is applied to the hyperons in a
nuclear medium. The hyperfine interaction due to the gluon exchange plays an
important role in the in-medium baryon spectra, while the pion-cloud effect is
relatively small. At the quark mean-field level, the feels more
attractive force than the \Sigma or \Xi in matter.Comment: 9 pages, 6 figure
Seismic Risk Evaluation of R.C. Buildings in Japan Designated in Accordance with the 1990 AIJ Guidelines
National Science Foundation Grant BCS 91-06390Kajima Foundatio
Disturbances of both cometary and Earth's magnetospheres excited by single solar flares
In the solar wind a comet plays the role of a windvane that moves three-dimensionally in the heliomagnetosphere. Among the solar systems bodies, only comets have a wide range of inclination angles of their orbital planes to the ecliptic plane ranging from 0 to 90 deg. Therefore, observations of cometary plasma tails are useful in probing the heliomagnetospheric conditions in the high heliolatitudinal region. A comet can be compared to a polar-orbiting probe encircling the Sun. We will introduce two rare cases in which the magnetospheres of both the comet and the Earth are disturbed by a single solar flare
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