9,207 research outputs found
Superpotentials of N=1 Supersymmetric Gauge Theories from M-theory
We consider brane configurations in M-theory describing N=1 supersymmetric
gauge theories and using the parametric representation of the brane
configurations, we calculate the superpotentials for various cases including
multiple gauge groups or fermions. For SU(n) N=1 SQCD with fermion case
(, we find that the superpotential from M-theory and the gauge
theory agree precisely. This gives a direct evidence of the validity of
Witten's M-theory method for calculating the super potential.Comment: 15pages, latex, typos corrected, a line regarding M\"obius
transformation in page 4 and angle dependence in page 12 correcte
Can a "credit crunch" be efficient?
Two observations have sometimes been viewed as evidence that the equilibrium allocations of intermediated credit markets are inefficient. First, low-income households' marginal propensity to consume is close to unity. Second, even high-income households seem to face nonprice constraints during recessions. This paper presents a model that possesses both of these features. (A recession is modeled as an economy in which the equilibrium level of investment is at its lowest possible level.) However, contrary to the conventional view, the equilibrium of this model is ex ante efficient. The model also sheds light on some historical episodes of credit restraint.Credit
A Single-Stage Low-Power Double-Balanced Mixer Merged with LNA and VCO
This paper proposes three types of single stage low-power RF front-end, called double-balanced LMVs, by merging LNA, mixer, and voltage-controlled oscillator (VCO) exploiting a series LC (SLC) network. The low intermediate frequency (IF) or baseband signal can be directly sensed at the drain nodes of the VCO switching transistors by adding a simple resistor-capacitor (RC) low-pass filter (LPF). By adopting a double-balanced mixer topology, the strong leakage of the local oscillator (LO) at the IF output is effectively suppressed. Using a 65 nm CMOS technology, the proposed double-balanced LMVs (DB-LMVs) are designed. Oscillating at around 2.4 GHz ISM band, the phase noise of the proposed three DB-LMVs is −111 dBc/Hz at 1 MHz offset frequency. The simulated voltage conversion gain is larger than 36 dB and the double-side band (DSB) noise figure (NF) is less than 7.7 dB. The DB-LMVs consume only 0.2 mW dc power from 1-V supply voltage
K*{\Lambda}(1116) photoproduction and nucleon resonances
In this presentation, we report our recent studies on the
photoproduction off the proton target, using the tree-level Born approximation,
via the effective Lagrangian approach. In addition, we include the nine (three-
or four-star confirmed) nucleon resonances below the threshold
MeV, to interpret the discrepancy between the
experiment and previous theoretical studies, in the vicinity of the threshold
region. From the numerical studies, we observe that the and
play an important role for the cross-section enhancement near
the . It also turns out that, in order to reproduce the
data, we have the vector coupling constants
and
.Comment: 2 pages, 2 figures, talk given at International Conference on the
structure of baryons, BARYONS'10, Dec. 7-11, 2010, Osaka, Japa
Determination of the parity of the pentaquark baryons : Theta^+ and Xi_5
We study determination of the parity of the pentaquark baryons in two
different processes. First, we investigate the Theta^+ production via the
vec{p} vec{p} -> Sigma^+ Theta^+ reaction process which was proposed to
determine unambiguously the parity of Theta^+. We observe the clear differences
in the total cross sections and the spin observable A_{xx}. As for the Xi_5 in
the bar{K} N -> K Xi_5 reaction process, the total cross section for the
positive parity presents about one hundred times lager than that of the
negative one due to the huge destructive interference.Comment: 5 pages, 8 figures, Talk given at International Workshop on
BARYONS04, Ecole polytechnique, Paris, France, 25-29 Oct 200
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