23,740 research outputs found
Chiral doublings of heavy-light hadrons: New charmed mesons discovered by BABAR,CLEO and BELLE
We remind the chiral doubling scenario [1,2] for hadrons built of heavy and
light quarks. Then we recall arguments why new states
D_s(2317),D_s(2460),D_0(2308) and D_1^'(2427) should be viewed as chiral
partners of D_s,D_s^*,D and D^*,respectively. We summarize with the list of
predictions based on chiral doubling scenario for other heavy-light hadrons.Comment: Talk at Hadron'03, Aschaffenburg, Germany, August 31st - September
6th, 2003. (5 pages, 1 figure
Thick-Film and LTCC Passive Components for High-Temperature Electronics
At this very moment an increasing interest in the field of high-temperature electronics is observed. This is a result of development in the area of wide-band semiconductors’ engineering but this also generates needs for passives with appropriate characteristics. This paper presents fabrication as well as electrical and stability properties of passive components (resistors, capacitors, inductors) made in thick-film or Low-Temperature Co-fired Ceramics (LTCC) technologies fulfilling demands of high-temperature electronics. Passives with standard dimensions usually are prepared by screen-printing whereas combination of standard screen-printing with photolithography or laser shaping are recommenced for fabrication of micropassives. Attainment of proper characteristics versus temperature as well as satisfactory long-term high-temperature stability of micropassives is more difficult than for structures with typical dimensions for thick-film and LTCC technologies because of increase of interfacial processes’ importance. However it is shown that proper selection of thick-film inks together with proper deposition method permit to prepare thick-film micropassives (microresistors, air-cored microinductors and interdigital microcapacitors) suitable for the temperature range between 150°C and 400°C
Study of Scalar Top Quarks in the Neutralino and Chargino Decay Channel
The scalar top discovery potential has been studied with a full-statistics
background simulation at sqrt(s)=500 GeV and L = 500 fb-1 for the TESLA
project. The beam polarization is very important to measure the scalar top
mixing angle and to determine its mass. The latest estimation of the beam
polarization parameters is applied. This study includes e+ polarization, which
improves the sensitivity. For a 180 GeV scalar top at minimum production cross
section, we obtain delta(m) = 0.8 GeV and delta(cosT) = 0.008 in the neutralino
decay channel, and delta(m) = 0.5 GeV and delta(cosT) = 0.004 in the chargino
decay channel.Comment: 4 pages, 6 figures, Proc. LCWS Chicago, November 200
Domain State Model for Exchange Bias
Monte Carlo simulations of a system consisting of a ferromagnetic layer
exchange coupled to a diluted antiferromagnetic layer described by a classical
spin model show a strong dependence of the exchange bias on the degree of
dilution in agreement with recent experimental observations on Co/CoO bilayers.
These simulations reveal that diluting the antiferromagnet leads to the
formation of domains in the volume of the antiferromagnet carrying a remanent
surplus magnetization which causes and controls exchange bias. To further
support this domain state model for exchange bias we study in the present paper
the dependence of the bias field on the thickness of the antiferromagnetic
layer. It is shown that the bias field strongly increases with increasing film
thickness and eventually goes over a maximum before it levels out for large
thicknesses. These findings are in full agreement with experiments.Comment: 8 pages latex, 3 postscript figure
On the coexistence of cooperators, defectors and conditional cooperators in the multiplayer iterated Prisoner's Dilemma
Recent experimental evidence [Gruji\'c et al., PLoS ONE 5, e13749 (2010)] on
the spatial Prisoner's Dilemma suggests that players choosing to cooperate or
not on the basis of their previous action and the actions of their neighbors
coexist with steady defectors and cooperators. We here study the coexistence of
these three strategies in the multiplayer iterated Prisoner's Dilemma by means
of the replicator dynamics. We consider groups with n = 2, 3, 4 and 5 players
and compute the payoffs to every type of player as the limit of a Markov chain
where the transition probabilities between actions are found from the
corresponding strategies. We show that for group sizes up to n = 4 there exists
an interior point in which the three strategies coexist, the corresponding
basin of attraction decreasing with increasing number of players, whereas we
have not been able to locate such a point for n = 5. We analytically show that
in the infinite n limit no interior points can arise. We conclude by discussing
the implications of this theoretical approach on the behavior observed in
experiments.Comment: 12 pages, 10 figures, uses elsart.cl
Phase Lags and Coherence of X-Ray Variability in Black Hole Candidates
The ``low'' (hard or ``non-thermal'') state of black hole candidates is
sometimes modelled via an optically thick, hot Compton cloud that obscures a
softer input source such as an accretion disk. In these models the observed
output spectra consist entirely of photons reprocessed by the cloud, making it
difficult to extract information about the input spectra. Recently Miller
(1995) has argued that the Fourier phase (or time) lag between hard and soft
X-ray photons in actuality represents the phase lags intrinsic to the input
source, modulo a multiplicative factor. The phase lags thus would be a probe of
the input photon source. In this paper we examine this claim and find that,
although true for the limited parameter space considered by Miller, the
intrinsic phase lag disappears whenever the output photon energy is much
greater than the input photon energy. The remaining time lags represent a
``shelf'' due to differences between mean diffusion times across the cloud. As
pointed out by Miller, the amplitude of this shelf -- which is present even
when the intrinsic time lags remain -- is indicative of the size and
temperature of the Compton cloud and is a function of the two energies being
compared. However, we find that with previous instruments such as Ginga the
shelf, if present, was likely obscured by counting noise. A more sensitive
measure of Compton cloud parameters may be obtainable from the coherence
function, which is derived from the amplitude of the Fourier cross power
spectral density. This function has been seen to exponentially decrease at high
Fourier frequencies in Cygnus X-1. Coherence loss is characteristic of Compton
clouds that undergo large variations of size and/or temperature on time scales
longer than about 10 seconds. We argue that observing phase lags and coherenceComment: 14 pages, uuencoded postscript, accepted for publication in Monthly
Notice
Probing non-orthogonality of eigenvectors in non-Hermitian matrix models: diagrammatic approach
Using large arguments, we propose a scheme for calculating the two-point
eigenvector correlation function for non-normal random matrices in the large
limit. The setting generalizes the quaternionic extension of free
probability to two-point functions. In the particular case of biunitarily
invariant random matrices, we obtain a simple, general expression for the
two-point eigenvector correlation function, which can be viewed as a further
generalization of the single ring theorem. This construction has some striking
similarities to the freeness of the second kind known for the Hermitian
ensembles in large . On the basis of several solved examples, we conjecture
two kinds of microscopic universality of the eigenvectors - one in the bulk,
and one at the rim. The form of the conjectured bulk universality agrees with
the scaling limit found by Chalker and Mehlig [JT Chalker, B Mehlig, PRL,
\textbf{81}, 3367 (1998)] in the case of the complex Ginibre ensemble.Comment: 20 pages + 4 pages of references, 12 figs; v2: typos corrected, refs
added; v3: more explanator
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