62,445 research outputs found
On sums of three squares
Let be the number of representations of a positive integer as a
sum of three squares of integers. We give two distinct proofs of a conjecture
of Wagon concerning the asymptotic value of the mean square of .Comment: 11 pages, minor revisions made; to appear in Internat. J. Number
Theor
Anti-correlated time lags in the Z source GX 5-1: Possible evidence for a truncated accretion disk
We investigate the nature of the inner accretion disk in the neutron star
source GX 5-1 by making a detailed study of time lags between X-rays of
different energies. Using the cross-correlation analysis, we found
anti-correlated hard and soft time lags of the order of a few tens to a few
hundred seconds and the corresponding intensity states were mostly the
horizontal branch (HB) and upper normal branch (NB). The model independent and
dependent spectral analysis showed that during these time lags the structure of
accretion disk significantly varied. Both eastern and western approaches were
used to unfold the X-ray continuum and systematic changes were observed in soft
and hard spectral components. These changes along with a systematic shift in
the frequency of quasi-periodic oscillations (QPOs) made it substantially
evident that the geometry of the accretion disk is truncated. Simultaneous
energy spectral and power density spectral study shows that the production of
the horizontal branch oscillations (HBOs) are closely related to the
Comptonizing region rather than the disk component in the accretion disk. We
found that as the HBO frequency decreases from the hard apex to upper HB, the
disk temperature increases along with an increase in the coronal temperature
which is in sharp contrast with the changes found in black hole binaries where
the decrease in QPO frequency is accompanied by a decrease in the disk
temperature and a simultaneous increase in the coronal temperature. We discuss
the results in the context of re-condensation of coronal material in the inner
region of the disk.Comment: 40 pages, 7 figures, accepted for publication in The Astrophysical
Journal Supplement (ApJS
Deconstruction and Gauge Theories in AdS_5
On a slice of AdS_5, despite having a dimensionful coupling, gauge theories
can exhibit logarithmic dependence on scale. In this paper, we utilize
deconstruction to analyze the scaling behavior of the theory, both above and
below the AdS curvature scale, and shed light on position-dependent
regularizations of the theory. We comment on applications to geometries other
than AdS.Comment: 15 pages, 1 figur
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
TeV scale partial mirage unification and neutralino dark matter
We study the TeV scale partial mirage unification scenario, where the gluino
and wino masses are degenerate around a TeV scale, but the bino mass is not
degenerate. This scenario has phenomenologically interesting aspects. First,
because of the degeneracy between the gluino and wino masses, this scenario
does not have the little hierarchy problem, that is, the higgisino mass is
around 150 GeV. The lightest superparticle is a mixture of the bino and
higgsino, and can lead to a right amount of thermal relic density as a dark
matter candidate
Intersecting Brane World from Type I Compactification
We elaborate that general intersecting brane models on orbifolds are obtained
from type I string compactifications and their T-duals. Symmetry breaking and
restoration occur via recombination and parallel separation of branes,
preserving supersymmetry. The Ramond-Ramond tadpole cancelation and the toron
quantization constrain the spectrum as a branching of the adjoints of SO(32),
up to orbifold projections. Since the recombination changes the gauge coupling,
the single gauge coupling of type I could give rise to different coupling below
the unification scale. This is due to the nonlocal properties of the
Dirac-Born-Infeld action. The weak mixing angle sin^2 theta_W = 3/8 is
naturally explained by embedding the quantum numbers to those of SO(10).Comment: 31 pages, 5 figure
Analog-digital simulation of transient-induced logic errors and upset susceptibility of an advanced control system
A simulation study is described which predicts the susceptibility of an advanced control system to electrical transients resulting in logic errors, latched errors, error propagation, and digital upset. The system is based on a custom-designed microprocessor and it incorporates fault-tolerant techniques. The system under test and the method to perform the transient injection experiment are described. Results for 2100 transient injections are analyzed and classified according to charge level, type of error, and location of injection
Gauge Theories in and Fine-Lattice Deconstruction
The logarithmic energy dependence of gauge couplings in AdS_5 emerges almost
automatically when the theory is deconstructed on a coarse lattice. Here we
study the theory away from the coarse-lattice limit. While we cannot
analytically calculate individual KK masses for a fine lattice, we can
calculate the product of all non-zero masses. This allows us to write down the
gauge coupling at low energies for any lattice-spacing and curvature. As
expected, the leading log behaviour is corrected by power-law contributions,
suppressed by the curvature. We then turn to intermediate energies, and discuss
the gauge coupling and the gauge boson profile in perturbation theory around
the coarse-lattice limit.Comment: 17 pages, 1 figure, typos in listing version of abstract correcte
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
The Gaugino Code
Gauginos might play a crucial role in the search for supersymmetry at the
Large Hadron Collider (LHC). Mass predictions for gauginos are rather robust
and often related to the values of the gauge couplings. We analyse the ratios
of gaugino masses in the LHC energy range for various schemes of supersymmetry
breakdown and mediation. Three distinct mass patterns emerge.Comment: 42 pages, Latex; a discussion of deflected anomaly mediation added,
references adde
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