12,137 research outputs found
Two-Higgs-Doublet-Models and Radiative CP Violation
We discuss the feasibility of spontaneous CP violation being induced by
radiative corrections in 2HDM's. Specifically, we analyze the cases of
gaugino/higgsino effect on MSSM, and a new model with an extra exotic quark
doublet. The new model, while demonstrating well the Georgi-Pais theorem, is
also expected to be phenomenlogically interesting.Comment: 8 pages + cover, 3 figures incoporated, in latex with aipproc.sty
/aipproc.cls, talk given by O.K. at MRST '9
Optimizing Administrative Mechanism of Trans-regional Science Park Collaborations in China—A Case Study of Yangtze River Delta S&T City
With several national strategies being brought up in China, innovation collaborations especially trans-regional innovation collaborations becoming increasingly important. This paper using the specific case of Yangtze River Delta S&T City —one inter-provincial cooperatively constructed Science Park in China— trying to improve administrations of trans-regional science parks. By field visiting and structured interviewing with major governments and related partners, this paper optimized current administrative structure of Yangtze River Delta S&T City that has hindered its development for years and provided experiences for similar trans-regional science park collaborations in China. Keywords: Trans-regional Science Park; Yangtze River Delta S&T City; Administration Structur
Resonant electron-lattice cooling in graphene
Controlling energy flows in solids through switchable electron-lattice
cooling can grant access to a range of interesting and potentially useful
energy transport phenomena. Here we discuss a unique switchable
electron-lattice cooling mechanism arising in graphene due to phonon emission
mediated by resonant scattering on defects in crystal lattice, which displays
interesting analogy to the Purcell effect in optics. This mechanism strongly
enhances the electron-phonon cooling rate, since non-equilibrium carriers in
the presence of momentum recoil due to disorder can access a larger phonon
phase space and emit phonons more effciently. Resonant energy dependence of
phonon emission translates into gate-tunable cooling rates, exhibiting giant
enhancement of cooling occurring when the carrier energy is aligned with the
electron resonance of the defect
Exploring Root Cause of Social Problems in China: Concept, Framework and Methodological Potential of Social Ecology
In China, the conflicts between economic development and social ethics caused by social transformation become increasingly prominent, thus triggering a series of novel social problems. These novel social problems are causing great damage to the stability of China’s society and therefore push us to search for a new theory or consummate an existing theory to illustrate the underlying mechanisms behind them. This paper argues the root cause of social problems in recent China lies in the absence of harmonious social connections and inadequate social resources after elaborating the concept of ‘social ecology’ and its conceptual model. We further illustrate the methodological potential of social ecology in solving social problems by exploring the dynamic equilibrium and disorder of social ecology and its causes. Keywords: Social Ecology; Social Ecological Systems Theory; Methodological Potentia
XMM-Newton Observations of NGC 247: X-ray Population and a Supersoft Ultraluminous X-ray Source
We report on a new XMM-Newton observation of NGC 247 from December 2009. The
galaxy contains a supersoft, ultraluminous X-ray source (ULX) whose spectrum
consists of a thermal component with a temperature about 0.1 keV and a
power-law tail with a photon index around 2.5. The thermal emission is
absolutely the dominant component, contributing 96% of the total luminosity in
the 0.3-10 keV band. Variability is detected at timescales of 10^2 s and longer
with a \nu^-1 power spectrum. These properties are consistent with black hole
binaries in the thermal state and suggest the presence of an intermediate mass
black hole of at least 600 solar masses. However, the integrated rms power is
much higher than typically found in the thermal state. An alternative
explanation of the emission could be a photosphere with a radius about 10^9 cm.
A possible absorption feature around 1 keV is detected, which may be due to
absorption of highly ionized winds. X-ray sources within the disk of NGC 247
have a luminosity function consistent with that found in low mass X-ray
binaries. We confirm previous results that X-rays from the quasar PHL 6625 may
be absorbed by gas in NGC 247, mainly at energies below 0.3 keV.Comment: accepted for publication in the Astrophysical Journa
Discovery of mHz X-ray Oscillations in a Transient Ultraluminous X-ray Source in M82
We report the discovery of X-ray quasi-periodic oscillations (QPOs) at
frequencies of 3-4 mHz from a transient ultraluminous X-ray source (ULX)
X42.3+59 in M82. The QPOs are strong and broad and appear with weak or absent
red noise, and are detected only in Chandra observations when the source is
brighter than 10^40 ergs/s. The QPO behavior is similar to the type A-I QPOs
found in XTE J1550-564, which is a subclass of low frequency QPOs with
properties in between type A and B. Therefore, we identify the QPOs in X42.3+59
as of type A or B, and rule out the possibility of type C. With this
identification, the mass of the black hole in X42.3+59 can be inferred as in
the range of 12,000-43,000 solar masses by scaling the QPO frequency to that of
the type A/B QPOs in stellar mass black holes. Cool disk emission is detected
in one Chandra observation, and the disk inner radius suggests a similar black
hole mass range. Black holes of such a high mass are able to produce an energy
output in a manner similar to X42.3+59 by accreting from the interstellar
medium directly.Comment: 5 pages, 1 figure, accepted for publication in The Astrophysical
Journal Letter
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