24,764 research outputs found
Muon g-2 anomaly and 125 GeV Higgs : Extra vector-like quark and LHC prospects
The ATLAS and CMS collaborations recently reported indication of a Higgs
boson around 125 GeV. If we add extra vector-like quarks to the MSSM, such a
relatively heavy Higgs can be naturally realized in the GMSB framework,
simultaneously explaining the muon g-2 anomaly. I will discuss LHC prospects of
this attractive model.Comment: 5 pages, 3 figures; talk given at the International Workshop on Grand
Unified Theories (GUT2012), Japan, 15-17 March 201
Upper-bounding bias errors in satellite navigation
A satellite navigation system for a safety critical application is required
to provide an integrity alert of any malfunction; the probability that a
navigation positioning error exceeds a given alert limit without an integrity
alert is required to be smaller than a given integrity risk. So far, a little
number of applications provide integrity alerts, because signal propagation
from a satellite to a receiver depends on diversified phenomena and makes
probabilistic upper-bound of possible threats difficult. To widen application
fields of satellite navigation, two methods to upper-bound wide classes of bias
errors are shown in this paper. The worst bias error in a maximum likelihood
estimate caused by an interference signal within a given small power is
derived. A novel inequality condition with a clock bias error and magnification
coefficients that upper-bounds a horizontal position error is presented.
Robustness of the inequality condition is numerically shown based on actual
configurations of satellites.Comment: To appear in IEEE Workshop on Statistical Signal Processing, Gold
Coast, Australia, 201
Effects of Relativistic Expansion on the Late-time Supernova Light Curves
The effects of relativistic expansion on the late-time supernova light curves
are investigated analytically, and a correction term to the (quasi-)exponential
decay is obtained by expanding the observed flux in terms of (\beta), where
(\beta) is the maximum velocity of the ejecta divided by the speed of light
(c). It is shown that the Doppler effect brightens the light curve owing to the
delayed decay of radioactive nuclei as well as to the Lorentz boosting of the
photon energies. The leading correction term is quadratic in (\beta), thus
being proportional to (E_{\rm k}/(M_{\rm ej} c^2)), where (E_{\rm k}) and
(M_{\rm ej}) are the kinetic energy of explosion and the ejecta mass. It is
also shown that the correction term evolves as a quadratic function of time
since the explosion. The relativistic effect is negligibly small at early
phases, but becomes of considerable size at late phases. In particular, for
supernove having a very large energy(hypernova) or exploding in a jet-like or
whatever non-spherical geometry, (^{56})Ni is likely to be boosted to higher
velocities and then we might see an appreciable change in flux. However, the
actual size of deviation from the (quasi-)exponential decay will be uncertain,
depending on other possible effects such as ionization freeze-out and
contributions from other energy sources that power the light curve.Comment: 12 pages including 2 figures, submitted to ApJ
Monetary and Fiscal Policy to Escape from a Deflationary Trap
This paper provides a theoretical overview of monetary and fiscal policy with the potential to engineer an exit from a deflationary trap, which we define here as sustained deflation in the presence of zero interest rates. We find that the required policy steps are an interest rate hike, a commitment to future currency growth, and a money-financed tax cut. The amount of tax cut required is equal to the increase in the central bank's payments to the treasury resulting from the higher inflation rate (nominal interest rate), while fiscal policymakers must maintain fiscal discipline by stabilizing government debt and the primary balance. There will be a temporary fall in output when prices are sticky, but this is the price that must be paid to conquer deflation. The current commitment to quantitative easing is based on the assumption that the natural interest rate has temporarily declined. If the economy is in a deflationary trap, however, the continuation of zero interest rates reinforces deflationary expectations and may make it perpetually impossible to eliminate deflation. Even under conditions in which the natural rate of interest seems to be positive, if deflation persists, it is probably wise to consider a policy approach that assumes deflationary trap conditions. With this in mind, we believe the conditions required for abandoning the current policy regime should include, in addition to consistently positive growth in the consumer price index (CPI), a consideration of the trend in real GDP.
Linear Absorption Spectrum of a Quantum Two-Dimensional Rotator Calculated Using a Rotationally Invariant System-Bath Hamiltonian
We consider a two-dimensional rigid rotator system coupled to a
two-dimensional heat bath. The Caldeira-Leggett (Brownian) model for the
rotator and the spin-Boson model have been used to describe such systems, but
they do not possess rotational symmetry, they cannot describe the discretized
rotational bands in absorption and emission spectra that have been found
experimentally. Here, to address this problem, we introduce a rotationally
invariant system-bath (RISB) model that is described by two sets of
harmonic-oscillator baths independently coupled to the rigid rotator as sine
and cosine functions of the rotator angle. Due to a difference in the energy
discretization of the total Hamiltonian, the dynamics described by the RISB
model differ significantly from those described by the rotational
Caldeira-Legget (RCL) model, while both models reduce to the Langevin equation
for a rotator in the classical limit. To demonstrate this point, we compute the
rotational absorption spectrum defined by the linear response function of a
rotator dipole. For this purpose, we derive a quantum master equation for the
RISB model in the high-temperature Markovian case. We find that the spectral
profiles of the calculated signals exhibit a transition from quantized
rotational bands to a single peak after spectrum collapse. This is a
significant finding, because previous approaches cannot describe such phenomena
in a unified manner.Comment: 20 pages 1 figur
"The Fiscal Investment and Loan Program in Transition"
This paper discusses the adequacy of the activities of the Fiscal Investment Loan Program agencies after the fundamental reform in April 2001, which disconnected postal savings and public pension reserves from the FILP. It is found that many ideas of justifying the government interventions to the financial sector have now lost their relevancy. The activity of government financial intermediaries should be streamlined. Among infrastructure construction projects, the most serious part of welfare loss lies on national motorway construction, which is estimated to be about 14.5 trillion yen of welfare loss.
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