96 research outputs found
Multi-quark baryons and color screening at finite temperature
We study baryons in SU(N) gauge theories at finite temperature according to
the gauge/string correspondence based on IIB string theory. The baryon is
constructed out of D5 brane and fundamental strings to form a color singlet
-quark bound state. At finite temperature and in the deconfining phase, we
could find -quark ``baryons''. Thermal properties of such -quark
baryons and also of the -quark baryon are examined. We study the temperature
dependence of color screening distance and Debye length of the baryon of
-quark and -quark. We also estimate the melting temperature, where the
baryons decay into quarks and gluons completely.Comment: 16 pages, 12 figure
String Junction Model, Cluster Hypothesis, Penta-Quark Baryon and Tetra-Quark Meson
Thirty years ago we proposed string junction model of hadrons and examined
structure and reaction of hadrons including exotic ones. Mass of exotic
hadrons of light quarks is roughly given by , where
is the total number of junctions and GeV is the ordinary light
baryon mass. In this paper we introduce "cluster hypothesis" into the model by
which mass of a complex hadron is given by the sum of masses of clusters
composing it. The hypothesis guarantees the established picture that mass
differences of hadrons of the same string junction structure are due to those
of the constituent quarks. A candidate for penta-quark baryon (1530
MeV, including a strange anti-quark {\sb} and that for tetra-quark
meson (4430 MeV) recently reported by the Bell collaboration are examined
in parallel. is considered to have non-strange partners, which are
lighter by the mass difference between strange and non-strange
quarks. Mass of such light penta-quark baryons with is expected to be
about 3 GeV. Several parameters of the model are estimated such as mass of
junction of MeV. While mass of light tetra-quark meson with
is expected to be about 2 GeV, (4430 MeV) containing
(u,c,{\db},{\cb}) gives a clue to determine some parameters of the model,
e.g., inter-junction string energy .Comment: 17 pages, 4 figures, correction is made, extensively revise
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