51,030 research outputs found
Gauge Threshold Corrections in Warped Geometry
We discuss the Kaluza-Klein threshold correction to low energy gauge
couplings in theories with warped extra-dimension, which might be crucial for
the gauge coupling unification when the warping is sizable. Explicit
expressions of one-loop thresholds are derived for generic 5D gauge theory on a
slice of AdS_5, where some of the bulk gauge symmetries are broken by orbifold
boundary conditions and/or by bulk Higgs vacuum values. Effects of the mass
mixing between the bulk fields with different orbifold parities are included as
such mixing is required in some class of realistic warped unification models.Comment: 33 pages, 1 figure, 6 tables, invited contribution to New Journal of
Physics Focus Issue on 'Extra Space Dimensions
Correct Effective Potential of Supersymmetric Yang-Mills Theory on M^4\times S^1
We study an supersymmetric Yang-Mills theory defined on
. The vacuum expectation values for adjoint scalar field in
vector multiplet, though important, has been overlooked in evaluating one-loop
effective potential of the theory. We correctly take the vacuum expectation
values into account in addition to the Wilson line phases to give an expression
for the effective potential, and gauge symmetry breaking is discussed. In
evaluating the potential, we employ the Scherk-Schwarz mechanism and introduce
bare mass for gaugino in order to break supersymmetry. We also obtain masses
for the scalars, the adjoint scalar, and the component gauge field for the
direction in case of the SU(2) gauge group. We observe that large
supersymmetry breaking gives larger mass for the scalar. This analysis is
easily applied to the case.Comment: 12 pages, 1 figur
Theory of Bubble Nucleation and Cooperativity in DNA Melting
The onset of intermediate states (denaturation bubbles) and their role during
the melting transition of DNA are studied using the Peyrard-Bishop-Daxuois
model by Monte Carlo simulations with no adjustable parameters. Comparison is
made with previously published experimental results finding excellent
agreement. Melting curves, critical DNA segment length for stability of bubbles
and the possibility of a two states transition are studied.Comment: 4 figures. Accepted for publication in Physical Review Letter
Sparticle masses in deflected mirage mediation
We discuss the sparticle mass patterns that can be realized in deflected
mirage mediation scenario of supersymmetry breaking, in which the moduli,
anomaly, and gauge mediations all contribute to the MSSM soft parameters.
Analytic expression of low energy soft parameters and also the sfermion mass
sum rules are derived, which can be used to interpret the experimentally
measured sparticle masses within the framework of the most general mixed
moduli-gauge-anomaly mediation. Phenomenological aspects of some specific
examples are also discussed.Comment: 43 pages, 17 figures, references adde
Giant phonon anomalies in the pseudo-gap phase of TiOCl
We report infrared and Raman spectroscopy results of the spin-1/2 quantum
magnet TiOCl. Giant anomalies are found in the temperature dependence of the
phonon spectrum, which hint to unusual coupling of the electronic degrees of
freedom to the lattice. These anomalies develop over a broad temperature
interval, suggesting the presence of an extended fluctuation regime. This
defines a pseudo-gap phase, characterized by a local spin-gap. Below 100 K a
dimensionality cross-over leads to a dimerized ground state with a global
spin-gap of about 2~430 K.Comment: 4 pages, 3 figures, for further information see
http://www.peter-lemmens.d
Running of Gauge Couplings in AdS5 via Deconstruction
Running of gauge couplings on a slice of AdS5 is examined using the
deconstruction set-up. Logarithmic running instead of (linear) power law is
justified when the cutoff is lower than the curvature scale. Most of
interesting features in warped gauge theory including the localization of
Kaluza-Klein modes, the widening of higher Kaluza-Klein spectrum spacing are
well captured within the framework of the deconstruction.Comment: 20 pages, 3 figures, revtex, refereces added and typos corrected; the
version published in JHE
Dynamical solution to the problem at TeV scale
We introduce a new confining force (\mu-color) at TeV scale to dynamically
generate a supersymmetry preserving mass scale which would replace the \mu
parameter in the minimal supersymmetric standard model (MSSM). We discuss the
Higgs phenomenology and also the pattern of soft supersymmetry breaking
parameters allowing the correct electroweak symmetry breaking within the
\mu-color model, which have quite distinctive features from the MSSM and also
from other generalizations of the MSSM.Comment: 12 pages, REVte
Ghosts and Tachyons in the Fifth Dimension
We present several solutions for the five dimensional gravity models in the
presence of bulk ghosts and tachyons to argue that these "troublesome" fields
can be a useful model-building tool. The ghost-like signature of the kinetic
term for a bulk scalar creates a minimum in the scale factor, removing the
necessity for a negative tension brane in models with the compactified fifth
dimension. It is shown that the model with the positive tension branes and a
ghost field in the bulk leads to the radion stabilization. The bulk scalar with
the variable sign kinetic term can be used to model both positive and negative
tension branes of a finite width in the compact dimension. Finally, we present
several ghost and tachyon field configurations in the bulk that lead to the
localization of gravity in four dimensions, including one solution with the
Gaussian profile for the metric, g_{\mu\nu}(y)=\eta_{\mu\nu}\exp{-\alpha y^2},
which leads to a stronger localization of gravity than the Randall-Sundrum
model.Comment: New references adde
Radius-dependent gauge unification in AdS5
We examine the relation of the 4-dimensional low energy coupling of bulk
gauge boson in a slice of AdS5 to the 5-dimensional fundamental couplings as a
function of the orbifold radius R. This allows us to address the gauge coupling
unification in AdS5 by means of the radius running as well as the conventional
momentum running. We then compute the radius dependence of 1-loop low energy
couplings in generic AdS5 theory with 4-dimensional supersymmetry, and discuss
the low energy predictions when the 5-dimensional couplings are assumed to be
unified.Comment: 11 pages, 2 figures, revtex, v3: analysis was generalized to
S^1/Z_2*Z_2 orbifoldin
New contribution to dimension five operators on proton decay in anomaly mediation scenario
In supergravity, effective superpotential relevant to dimension five
operators on proton decay processes also leads to supersymmetry breaking terms
among sfermions, dimension four operators. These dimension four operators
induce the dimension five operators through 1-loop diagrams dressed by
gauginos. We find that, in a class of models with the anomaly mediation, the
1-loop contributions can be comparable to those at the tree level. Therefore,
such operators have a great impact on proton decay rate. Depending on a
universal phase of gaugino masses and soft mass spectrum, the proton decay rate
can be enhanced or suppressed.Comment: 8 pages, no figure. A few minor changes have been mad
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