315 research outputs found
Two- and three-point Green's functions in two-dimensional Landau-gauge Yang-Mills theory
The ghost and gluon propagator and the ghost-gluon and three-gluon vertex of
two-dimensional SU(2) Yang-Mills theory in (minimal) Landau gauge are studied
using lattice gauge theory. It is found that the results are qualitatively
similar to the ones in three and four dimensions. The propagators and the
Faddeev-Popov operator behave as expected from the Gribov-Zwanziger scenario.
In addition, finite volume effects affecting these Green's functions are
investigated systematically. The critical infrared exponents of the
propagators, as proposed in calculations using stochastic quantization and
Dyson-Schwinger equations, are confirmed quantitatively. For this purpose
lattices of volume up to (42.7 fm)^2 have been used.Comment: 14 pages, 14 figures, 4 tables, references adde
Nontriviality of Gauge-Higgs-Yukawa System and Renormalizability of Gauged NJL Model
In the leading order of a modified 1/Nc expansion, we show that a class of
gauge-Higgs-Yukawa systems in four dimensions give non-trivial and well-defined
theories in the continuum limit. The renormalized Yukawa coupling y and the
quartic scalar coupling \lambda have to lie on a certain line in the
(y,\lambda) plane and the line terminates at an upper bound. The gauged
Nambu--Jona-Lasinio (NJL) model in the limit of its ultraviolet cutoff going to
infinity, is shown to become equivalent to the gauge-Higgs-Yukawa system with
the coupling constants just on that terminating point. This proves the
renormalizability of the gauged NJL model in four dimensions. The effective
potential for the gauged NJL model is calculated by using renormalization group
technique and confirmed to be consistent with the previous result by Kondo,
Tanabashi and Yamawaki obtained by the ladder Schwinger-Dyson equation.Comment: 32 pages, LaTeX, 3 Postscript Figures are included as uuencoded files
(need `epsf.tex'), KUNS-1278, HE(TH) 94/10 / NIIG-DP-94-2. (Several
corrections in the introduction and references.
Infrared properties of propagators in Landau-gauge pure Yang-Mills theory at finite temperature
The finite-temperature behavior of gluon and of Faddeev-Popov-ghost
propagators is investigated for pure SU(2) Yang-Mills theory in Landau gauge.
We present nonperturbative results, obtained using lattice simulations and
Dyson-Schwinger equations. Possible limitations of these two approaches, such
as finite-volume effects and truncation artifacts, are extensively discussed.
Both methods suggest a very different temperature dependence for the magnetic
sector when compared to the electric one. In particular, a clear thermodynamic
transition seems to affect only the electric sector. These results imply in
particular the confinement of transverse gluons at all temperatures and they
can be understood inside the framework of the so-called Gribov-Zwanziger
scenario of confinement.Comment: 25 pages, 14 figures, 2 tables, minor changes of typographical and
design character, some minor errors corrected, version to appear in PR
SUSY flavor structure of generic 5D supergravity models
We perform a comprehensive and systematic analysis of the SUSY flavor
structure of generic 5D supergravity models on with multiple
-odd vector multiplets that generate multiple moduli. The SUSY flavor
problem can be avoided due to contact terms in the 4D effective K\"ahler
potential peculiar to the multi-moduli case. A detailed phenomenological
analysis is provided based on an illustrative model.Comment: 37 pages, 7 figures, Sec.4 is modifie
Quantum Fields a la Sylvester and Witt
A structural explanation of the coupling constants in the standard model, i.e
the fine structure constant and the Weinberg angle, and of the gauge fixing
contributions is given in terms of symmetries and representation theory. The
coupling constants are normalizations of Lorentz invariantly embedded little
groups (spin and polarization) arising in a harmonic analysis of quantum vector
fields. It is shown that the harmonic analysis of massless fields requires an
extension of the familiar Fourier decomposition, containing also indefinite
unitary nondecomposable time representations. This is illustrated by the
nonprobabilistic contributions in the electromagnetic field.Comment: 18 pages LaTeX file (62 kB), all macros are include
Gauged Symmetries and Fayet-Iliopoulos Terms in 5D Orbifold Supergravity
We discuss a gauged supergravity on five-dimensional (5D) orbifold
() in which both a -even U(1) gauge field and the -odd
graviphoton take part in the gauging. Based on the off-shell
formulation of 5D supergravity, we analyze the structure of Fayet-Iliopoulos
(FI) terms allowed in such model. Introducing a -even gauge field
accompanies new bulk and boundary FI terms in addition to the known integrable
boundary FI term which could be present in the absence of any gauged
symmetry. Some physical consequences of these new FI terms are examined.Comment: 1+17 pages, 9 figures, typeset in JHEP styl
The anomalous dimension of the composite operator A^2 in the Landau gauge
The local composite operator A^2 is analysed in pure Yang-Mills theory in the
Landau gauge within the algebraic renormalization. It is proven that the
anomalous dimension of A^2 is not an independent parameter, being expressed as
a linear combination of the gauge beta function and of the anomalous dimension
of the gauge fields.Comment: 12 pages, LaTeX2e, final version to appear in Phys. Lett.
Geometrically Induced Gauge Structure on Manifolds Embedded in a Higher Dimensional Space
We explain in a context different from that of Maraner the formalism for
describing motion of a particle, under the influence of a confining potential,
in a neighbourhood of an n-dimensional curved manifold M^n embedded in a
p-dimensional Euclidean space R^p with p >= n+2. The effective Hamiltonian on
M^n has a (generally non-Abelian) gauge structure determined by geometry of
M^n. Such a gauge term is defined in terms of the vectors normal to M^n, and
its connection is called the N-connection. In order to see the global effect of
this type of connections, the case of M^1 embedded in R^3 is examined, where
the relation of an integral of the gauge potential of the N-connection (i.e.,
the torsion) along a path in M^1 to the Berry's phase is given through Gauss
mapping of the vector tangent to M^1. Through the same mapping in the case of
M^1 embedded in R^p, where the normal and the tangent quantities are exchanged,
the relation of the N-connection to the induced gauge potential on the
(p-1)-dimensional sphere S^{p-1} (p >= 3) found by Ohnuki and Kitakado is
concretely established. Further, this latter which has the monopole-like
structure is also proved to be gauge-equivalent to the spin-connection of
S^{p-1}. Finally, by extending formally the fundamental equations for M^n to
infinite dimensional case, the present formalism is applied to the field theory
that admits a soliton solution. The resultant expression is in some respects
different from that of Gervais and Jevicki.Comment: 52 pages, PHYZZX. To be published in Int. J. Mod. Phys.
Massive gravity as a quantum gauge theory
We present a new point of view on the quantization of the massive
gravitational field, namely we use exclusively the quantum framework of the
second quantization. The Hilbert space of the many-gravitons system is a Fock
space where the one-particle Hilbert
space carries the direct sum of two unitary irreducible
representations of the Poincar\'e group corresponding to two particles of mass
and spins 2 and 0, respectively. This Hilbert space is canonically
isomorphic to a space of the type where is a gauge charge
defined in an extension of the Hilbert space
generated by the gravitational field and some ghosts fields
(which are vector Fermi fields) and (which
are vector field Bose fields.)
Then we study the self interaction of massive gravity in the causal
framework. We obtain a solution which goes smoothly to the zero-mass solution
of linear quantum gravity up to a term depending on the bosonic ghost field.
This solution depends on two real constants as it should be; these constants
are related to the gravitational constant and the cosmological constant. In the
second order of the perturbation theory we do not need a Higgs field, in sharp
contrast to Yang-Mills theory.Comment: 35 pages, no figur
Embedding of the Bosonic String into the String
We investigate new realisations of the algebra with arbitrary central
charge, making use of the fact that this algebra can be linearised by the
inclusion of a spin-1 current. We use the new realisations with and
to build non-critical and critical BRST operators. Both of these
can be converted by local canonical transformations into a BRST operator for
the Virasoro string with , together with a Kugo-Ojima topological term.
Consequently, these new realisations provide embeddings of the Virasoro string
into non-critical and critical strings.Comment: 11 pages. (Some referencing changes
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