50,262 research outputs found
KN and KbarN Elastic Scattering in the Quark Potential Model
The KN and KbarN low-energy elastic scattering is consistently studied in the
framework of the QCD-inspired quark potential model. The model is composed of
the t-channel one-gluon exchange potential, the s-channel one-gluon exchange
potential and the harmonic oscillator confinement potential. By means of the
resonating group method, nonlocal effective interaction potentials for the KN
and KbarN systems are derived and used to calculate the KN and KbarN elastic
scattering phase shifts. By considering the effect of QCD renormalization, the
contribution of the color octet of the clusters (qqbar) and (qqq) and the
suppression of the spin-orbital coupling, the numerical results are in fairly
good agreement with the experimental data.Comment: 20 pages, 8 figure
Real and Monetary Convergence within the European Union and Between the European Union and Candidate Countries: A Rolling Cointegration Approach
We use rolling cointegration to measure the convergence of base money, M2, the consumer price index and industrial output between two reference countries, Germany and France, and recent EU members and some transition economy candidates. Counties that recently joined the EU exhibit time-varying cointegration with the reference countries over much of the 1980-2000 sample period. Cointegration for the transition economies was comparable for M2 and prices, but less so for monetary policy and industrial output. This suggests that a peg to the Euro upon accession is feasible for the East European candidates, but the benefits of joining the Euro zone are as yet limited.http://deepblue.lib.umich.edu/bitstream/2027.42/39842/3/wp458.pd
Non-volatile resistive switching in dielectric superconductor YBCO
We report on the reversible, nonvolatile and polarity dependent resistive
switching between superconductor and insulator states at the interfaces of a
Au/YBaCuO (YBCO)/Au system. We show that the
superconducting state of YBCO in regions near the electrodes can be reversibly
removed and restored. The possible origin of the switching effect may be the
migration of oxygen or metallic ions along the grain boundaries that control
the intergrain superconducting coupling. Four-wire bulk resistance measurements
reveal that the migration is not restricted to interfaces and produce
significant bulk effects.Comment: 4 pages, 4 figures, corresponding author: C. Acha ([email protected]
Dirac-Schr\"odinger equation for quark-antiquark bound states and derivation of its interaction kerne
The four-dimensional Dirac-Schr\"odinger equation satisfied by
quark-antiquark bound states is derived from Quantum Chromodynamics. Different
from the Bethe-Salpeter equation, the equation derived is a kind of first-order
differential equations of Schr\"odinger-type in the position space. Especially,
the interaction kernel in the equation is given by two different closed
expressions. One expression which contains only a few types of Green's
functions is derived with the aid of the equations of motion satisfied by some
kinds of Green's functions. Another expression which is represented in terms of
the quark, antiquark and gluon propagators and some kinds of proper vertices is
derived by means of the technique of irreducible decomposition of Green's
functions. The kernel derived not only can easily be calculated by the
perturbation method, but also provides a suitable basis for nonperturbative
investigations. Furthermore, it is shown that the four-dimensinal
Dirac-Schr\"odinger equation and its kernel can directly be reduced to rigorous
three-dimensional forms in the equal-time Lorentz frame and the
Dirac-Schr\"odinger equation can be reduced to an equivalent
Pauli-Schr\"odinger equation which is represented in the Pauli spinor space. To
show the applicability of the closed expressions derived and to demonstrate the
equivalence between the two different expressions of the kernel, the t-channel
and s-channel one gluon exchange kernels are chosen as an example to show how
they are derived from the closed expressions. In addition, the connection of
the Dirac-Schr\"odinger equation with the Bethe-Salpeter equation is discussed
Real and monetary convergence within the European Union and between the European Union and candidate countries: A rolling cointegration approach
We use rolling cointegration to measure the convergence of base money, M2, the consumer price index and industrial output between two reference countries, Germany and France, and recent EU members and some transition economy candidates. Counties that recently joined the EU exhibit time-varying cointegration with the reference countries over much of the 1980-2000 sample period. Cointegration for the transition economies was comparable for M2 and prices, but less so for monetary policy and industrial output. This suggests that a peg to the Euro upon accession is feasible for the East European candidates, but the benefits of joining the Euro zone are as yet limited. --European Union,convergence,currency areas,enlargement,cointegration,policy coordination
Real and Monetary Convergence within the European Union and Between the European Union and Candidate Countries: A Rolling Cointegration Approach
We use rolling cointegration to measure the convergence of base money, M2, the consumer price index and industrial output between two reference countries, Germany and France, and recent EU members and some transition economy candidates. Counties that recently joined the EU exhibit time-varying cointegration with the reference countries over much of the 1980-2000 sample period. Cointegration for the transition economies was comparable for M2 and prices, but less so for monetary policy and industrial output. This suggests that a peg to the Euro upon accession is feasible for the East European candidates, but the benefits of joining the Euro zone are as yet limited.European Union, convergence, currency areas, enlargement, cointegration, policy coordination
Strange meson-nucleon states in the quark potential model
The quark potential model and resonating group method are used to investigate
the bound states and/or resonances. The model potential consists of
the t-channel and s-channel one-gluon exchange potentials and the confining
potential with incorporating the QCD renormalization correction and the
spin-orbital suppression effect in it. It was shown in our previous work that
by considering the color octet contribution, use of this model to investigate
the low energy elastic scattering leads to the results which are in pretty
good agreement with the experimental data. In this paper, the same model and
method are employed to calculate the masses of the bound systems.
For this purpose, the resonating group equation is transformed into a standard
Schr\"odinger equation in which a nonlocal effective interaction
potential is included. Solving the Schr\"odinger equation by the variational
method, we are able to reproduce the masses of some currently concerned
states and get a view that these states possibly exist as
molecular states. For the system, the same calculation gives no support to
the existence of the resonance which was announced
recently.Comment: 15 pages, 4 figure
Autonomous Integrated Receive System (AIRS) requirements definition. Volume 3: Performance and simulation
The autonomous and integrated aspects of the operation of the AIRS (Autonomous Integrated Receive System) are discussed from a system operation point of view. The advantages of AIRS compared to the existing SSA receive chain equipment are highlighted. The three modes of AIRS operation are addressed in detail. The configurations of the AIRS are defined as a function of the operating modes and the user signal characteristics. Each AIRS configuration selection is made up of three components: the hardware, the software algorithms and the parameters used by these algorithms. A comparison between AIRS and the wide dynamics demodulation (WDD) is provided. The organization of the AIRS analytical/simulation software is described. The modeling and analysis is for simulating the performance of the PN subsystem is documented. The frequence acquisition technique using a frequency-locked loop is also documented. Doppler compensation implementation is described. The technological aspects of employing CCD's for PN acquisition are addressed
- …