110 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
Accelerated Quark and Holography for Confining Gauge theory
We show a constantly accelerated quark as a string solution of the Nambu-Goto
action, which is embedded in the bulk background dual to the
supersymmetric confining Yang-Mills theory. The induced metric of the world
sheet for this string solution has an event horizon specified by the fifth
coordinate. By an extended Rindler transformation proposed by Xiao, we move to
the comoving frame of the accelerated quark-string. Then we find that this
horizon is transferred to the event horizon of the bulk and the causal part of
the accelerated quark is transformed to a static free-quark in the Rindler
coordinate. As a result, the confinement of the Minkowski vacuum is lost in the
Rindler vacuum. This point is assured also by studying the potential between
the quark and anti-quark. However, the remnants of the original confining force
are seen in various thermal quantities. We also discuss the consistency of our
results and the claim that the Green's functions will not be changed by the
Rindler transformation.Comment: 25 pages, 7 figure
D3/D7 holographic Gauge theory and Chemical potential
N=2 supersymmetric Yang-Mills theory with flavor hypermultiplets at finite
temperature and in the dS are studied for finite quark number density
() by a dual supergravity background with non-trivial dilaton and axion.
The quarks and its number density are introduced by embedding a probe D7
brane. We find a critical value of the chemical potential at the limit of
, and it coincides with the effective quark mass given in each theory
for . At this point, a transition of the D7 embedding configurations
occurs between their two typical ones. The phase diagrams of this transition
are shown in the plane of chemical potential versus temperature and
cosmological constant for YM theory at finite temperature and in dS
respectively. In this phase transition, the order parameter is considered as
. % and the critical value of the chemical potential This result seems to
be reasonable since both theories are in the quark deconfinement phase.Comment: 17 pages, 8 figure
Minimum Supersymmetric Standard Model on the Noncommutative Geometry
We have obtained the supersymmetric extension of spectral triple which
specify a noncommutative geometry(NCG). We assume that the functional space H
constitutes of wave functions of matter fields and their superpartners included
in the minimum supersymmetric standard model(MSSM). We introduce the internal
fluctuations to the Dirac operator on the manifold as well as on the finite
space by elements of the algebra A in the triple. So, we obtain not only the
vector supermultiplets which meditate SU(3)xSU(2)xU(1)_Y gauge degrees of
freedom but also Higgs supermultiplets which appear in MSSM on the same
standpoint. Accoding to the supersymmetric version of the spectral action
principle, we calculate the square of the fluctuated total Dirac operator and
verify that the Seeley-DeWitt coeffients give the correct action of MSSM. We
also verify that the relation between coupling constants of , and
is same as that of SU(5) unification theory
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