10,642 research outputs found
Reconstruction of the spontaneously broken gauge theory in non-commutative geometry
The scheme previously proposed by the present authors is modified to
incorporate the strong interaction by affording the direct product internal
symmetry. We do not need to prepare the extra discrete space for the color
gauge group responsible for the strong interaction to reconstruct the standard
model and the left-right symmetric gauge model(LRSM). The approach based on
non-commutative geometry leads us to presents many attractive points such as
the unified picture of the gauge and Higgs field as the generalized connection
on the discrete space; Minkowski space multipied by N-points discrete space.
This approach leads us to unified picture of gauge and Higgs fields as the
generalized connection. The standard model needs N=2 discrete space for
reconstruction in this formalism. \lr is still alive as a model with the
intermediate symmetry of the spontaneously broken SO(10) grand unified
theory(GUT). N=3 discrete space is needed for the reconstruction of LRSM to
include two Higgs bosons and which are as usual transformed as
(2,2*,0)$ and (1,3,-2) under left-handed SU(2)x right-handed SU(2)x U(1),
respectively. xi is responsible to make the right handed-neutrino Majorana
fermion and so well explains the seesaw mechanism. Up and down quarks have the
different masses through the vacuum expectation value of phi.Comment: 21 page
Field Theory in Noncommutative Minkowski Superspace
There is much discussion of scenarios where the space-time coordinates x^\mu
are noncommutative. The discussion has been extended to include nontrivial
anticommutation relations among spinor coordinates in superspace. A number of
authors have studied field theoretical consequences of the deformation of N=1
superspace arising from nonanticommutativity of coordinates \theta, while
leaving \bar{theta}'s anticommuting. This is possible in Euclidean superspace
only. In this note we present a way to extend the discussion by making both
\theta and \bar{theta} coordinates non-anticommuting in Minkowski superspace.
We present a consistent algebra for the supercoordinates, find a star-product,
and give the Wess-Zumino Lagrangian L_{WZ} within our model. It has two extra
terms due to non(anti)commutativity. The Lagrangian in Minkowski superspace is
always manifestly Hermitian and for L_{WZ} it preserves Lorentz invariance.Comment: 8 pages, added references, two-column format, published in PR
Quaternion Octonion Reformulation of Quantum Chromodynamics
We have made an attempt to develop the quaternionic formulation of Yang -
Mill's field equations and octonion reformulation of quantum chromo dynamics
(QCD). Starting with the Lagrangian density, we have discussed the field
equations of SU(2) and SU(3) gauge fields for both cases of global and local
gauge symmetries. It has been shown that the three quaternion units explain the
structure of Yang- Mill's field while the seven octonion units provide the
consistent structure of SU(3)_{C} gauge symmetry of quantum chromo dynamics
BRST invariant Lagrangian of spontaneously broken gauge theories in noncommutative geometry
The quantization of spontaneously broken gauge theories in noncommutative
geometry(NCG) has been sought for some time, because quantization is crucial
for making the NCG approach a reliable and physically acceptable theory. Lee,
Hwang and Ne'eman recently succeeded in realizing the BRST quantization of
gauge theories in NCG in the matrix derivative approach proposed by Coquereaux
et al. The present author has proposed a characteristic formulation to
reconstruct a gauge theory in NCG on the discrete space .
Since this formulation is a generalization of the differential geometry on the
ordinary manifold to that on the discrete manifold, it is more familiar than
other approaches. In this paper, we show that within our formulation we can
obtain the BRST invariant Lagrangian in the same way as Lee, Hwang and Ne'eman
and apply it to the SU(2)U(1) gauge theory.Comment: RevTeX, page
Quaternion-Octonion SU(3) Flavor Symmetry
Starting with the quaternionic formulation of isospin SU(2) group, we have
derived the relations for different components of isospin with quark states.
Extending this formalism to the case of SU(3) group we have considered the
theory of octonion variables. Accordingly, the octonion splitting of SU(3)
group have been reconsidered and various commutation relations for SU(3) group
and its shift operators are also derived and verified for different iso-spin
multiplets i.e. I, U and V- spins.
Keywords: SU(3), Quaternions, Octonions and Gell Mann matrices
PACS NO: 11.30.Hv: Flavor symmetries; 12.10-Dm: Unified field theories and
models of strong and electroweak interaction
In-medium modification of P-wave charmonia from QCD sum rules
We investigate the changes of the masses and widths of and
in hot gluonic matter near and in nuclear medium using QCD
sum rules. As in the previous works for the and , in-medium
effects are incorporated through the changes of gluon condensates. Twist-2
terms for the and are also included
for the first time. The results show that larger mass shifts and width
broadenings take place as compared to the -wave states. As the critical
change take place near , related measurements can reveal critical
phenomenon in QCD.Comment: 7 pages, 6 figures, to be published in Phys.Rev.
Residue network in protein native structure belongs to the universality class of three dimensional critical percolation cluster
A single protein molecule is regarded as a contact network of amino-acid
residues. Some studies have indicated that this network is a small world
network (SWN), while other results have implied that this is a fractal network
(FN). However, SWN and FN are essentially different in the dependence of the
shortest path length on the number of nodes. In this paper, we investigate this
dependence in the residue contact networks of proteins in native structures,
and show that the networks are not SWN but FN. FN is generally characterized by
several dimensions. Among them, we focus on three dimensions; the network
topological dimension , the fractal dimension , and the spectral
dimension . We find that proteins universally yield ,
and . These values are in surprisingly good
coincidence with those in three dimensional critical percolation cluster. Hence
the residue contact networks in the protein native structures belong to the
universality class of three dimensional percolation cluster. The criticality is
relevant to the ambivalent nature of the protein native structures, i.e., the
coexistence of stability and instability, both of which are necessary for a
protein to function as a molecular machine or an allosteric enzyme.Comment: 4 pages, 3 figure
Critical Behavior of J/psi across the Phase Transition from QCD sum rules
We study behavior of J/psi in hot gluonic matter using
QCD sum rules. Taking into account temperature dependences of the gluon
condensates extracted from lattice thermodynamics for the pure SU(3) system, we
find that the mass and width of J/psi exhibit rapid change across the critical
temperature.Comment: 5 pages, 3 figures. Poster contribution for Quark Matter 2008. To be
published in the proceeding
On the Energy Required to Eject Processed Matter from Galaxies
We evaluate the minimum energy input rate that starbursts require for
expelling their newly processed matter from their host galaxies. Special
attention is given to the pressure caused by the environment in which a galaxy
is situated, as well as to the intrinsic rotation of the gaseous component. We
account for these factors and for a massive dark matter distribution, and
develop a self-consistent solution for the interstellar matter gas
distribution. Our results are in excellent agreement with the results of Mac
Low & Ferrara (1999) for galaxies with a flattened disk-like ISM density
distribution and a low intergalactic gas pressure ( 1
cm K). However, our solution also requires a much larger energy input
rate threshold when one takes into consideration both a larger intergalactic
pressure and the possible existence of a low-density, non-rotating, extended
gaseous halo component.Comment: 7 pages, 4 figures, 1 table, Accepted for publication in Ap
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