384 research outputs found
Production of photons by the parametric resonance in the dynamical Casimir effect
We calculate the number of photons produced by the parametric resonance in a
cavity with vibrating walls. We consider the case that the frequency of
vibrating wall is which is a generalization of other
works considering only , where is the fundamental-mode
frequency of the electromagnetic field in the cavity. For the calculation of
time-evolution of quantum fields, we introduce a new method which is borrowed
from the time-dependent perturbation theory of the usual quantum mechanics.
This perturbation method makes it possible to calculate the photon number for
any and to observe clearly the effect of the parametric resonance.Comment: 15 pages, RevTeX, no figure
Interference phenomena in the photon production between two oscillating walls
We study the photon production in a 1D cavity whose left and right walls
oscillate with the frequency and , respectively. For
the number of generated photons by the
parametric resonance is the sum of the photon numbers produced when the left
and the right wall oscillates separately. But for ,
the interference term proportional to is found additionally, where
is the phase difference between two oscillations of the walls.Comment: 7 pages, RevTeX, no figures, a sign error correcte
Topological dilaton black holes
In four-dimensional spacetime, when the two-sphere of black hole event
horizons is replaced by a two-dimensional hypersurface with zero or negative
constant curvature, the black hole is referred to as a topological black hole.
In this paper we present some exact topological black hole solutions in the
Einstein-Maxwell-dilaton theory with a Liouville-type dilaton potential.Comment: 8 pages, Revtex, no figure
Singlet-doublet Higgs mixing and its implications on the Higgs mass in the PQ-NMSSM
We examine the implications of singlet-doublet Higgs mixing on the properties
of a Standard Model (SM)-like Higgs boson within the Peccei-Quinn invariant
extension of the NMSSM (PQ-NMSSM). The SM singlet added to the Higgs sector
connects the PQ and visible sectors through a PQ-invariant non-renormalizable
K\"ahler potential term, making the model free from the tadpole and domain-wall
problems. For the case that the lightest Higgs boson is dominated by the
singlet scalar, the Higgs mixing increases the mass of a SM-like Higgs boson
while reducing its signal rate at collider experiments compared to the SM case.
The Higgs mixing is important also in the region of parameter space where the
NMSSM contribution to the Higgs mass is small, but its size is limited by the
experimental constraints on the singlet-like Higgs boson and on the lightest
neutralino constituted mainly by the singlino whose Majorana mass term is
forbidden by the PQ symmetry. Nonetheless the Higgs mixing can increase the
SM-like Higgs boson mass by a few GeV or more even when the Higgs signal rate
is close to the SM prediction, and thus may be crucial for achieving a 125 GeV
Higgs mass, as hinted by the recent ATLAS and CMS data. Such an effect can
reduce the role of stop mixing.Comment: 26 pages, 3 figures; published in JHE
Photometric Selection of Unobscured QSOs in the Ecliptic Poles: KMTNet in the South Field and Pan-STARRS in the North Field
We search for quasi-stellar objects (QSOs) in a wide area of the south
ecliptic pole (SEP) field, which has been and will continue to be intensively
explored through various space missions. For this purpose, we obtain deep
broadband optical images of the SEP field covering an area of
deg with the Korea Microlensing Telescope Network.
The 5 detection limits for point sources in the bands are
estimated to be 22.59, 22.60, 22.98, and 21.85 mag, respectively.
Utilizing data from Wide-field Infrared Survey Explorer, unobscured QSO
candidates are selected among the optically point-like sources using the
mid-infrared (MIR) and optical-MIR colors. To further refine our selection and
eliminate any contamination not adequately removed by the color-based
selection, we perform the spectral energy distribution fitting with archival
photometric data ranging from optical to MIR. As a result, we identify a total
of 2,383 unobscured QSO candidates in the SEP field. We also apply a similar
method to the north ecliptic pole field using the Pan-STARRS data and obtain a
similar result of identifying 2,427 candidates. The differential number count
per area of our QSO candidates is in good agreement with those measured from
spectroscopically confirmed ones in other fields. Finally, we compare the
results with the literature and discuss how this work will be implicated in
future studies, especially with the upcoming space missions.Comment: 14 pages, 9 figures, accepted for publication in ApJ
Light Higgsino in Heavy Gravitino Scenario with Successful Electroweak Symmetry Breaking
We consider, in the context of the minimal supersymmetric standard model, the
case where the gravitino weighs 10^6 GeV or more, which is preferred by various
cosmological difficulties associated with unstable gravitinos. Despite the
large Higgs mixing parameter B together with the little hierarchy to other soft
supersymmetry breaking masses, a light higgsino with an electroweak scale mass
leads to successful electroweak symmetry breaking, at the price of fine-tuning
the higgsino mixing mu parameter. Furthermore the light higgsinos produced at
the decays of gravitinos can constitute the dark matter of the universe. The
heavy squark mass spectrum of O(10^4) GeV can increase the Higgs boson mass to
about 125 GeV or higher.Comment: 13 pages, 3 figures; v2: version to appear in JHE
Scherk-Schwarz Supersymmetry Breaking for Quasi-localized Matter Fields and Supersymmetry Flavor Violation
We examine the soft supersymmetry breaking parameters induced by the
Scherk-Schwarz (SS) boundary condition in 5-dimensional orbifold field theory
in which the quark and lepton zero modes are quasi-localized at the orbifold
fixed points to generate the hierarchical Yukawa couplings. In such theories,
the radion corresponds to a flavon to generate the flavor hierarchy and at the
same time plays the role of the messenger of supersymmetry breaking. As a
consequence, the resulting soft scalar masses and trilinear -parameters of
matter zero modes at the compactification scale are highly flavor-dependent,
thereby can lead to dangerous flavor violations at low energy scales. We
analyze in detail the low energy flavor violations in SS-dominated
supersymmetry breaking scenario under the assumption that the compactification
scale is close to the grand unification scale and the 4-dimensional effective
theory below the compactification scale is given by the minimal supersymmetric
standard model. Our analysis can be applied to any supersymmetry breaking
mechanism giving a sizable -component of the radion superfield, e.g. the
hidden gaugino condensation model.Comment: revtex4, 22 pages, some numerical errors are corrected in
phenomenological analysis, main conclusion does not chang
Sequestered uplifting and the pattern of soft supersymmetry breaking terms
We examine the pattern of soft supersymmetry breaking terms in moduli
stabilization, where an uplifting potential is provided by spontaneously broken
supersymmetry in a generic sequestered sector. From stationary conditions, we
derive the relation between moduli F-term vacuum expectation values which does
not depend on the details of sequestered uplifting. This moduli F-term relation
is crucial for identifying the dominant source of soft terms of visible fields.Comment: 11 pages; references adde
MRI classification of interspinous ligament degeneration of the lumbar spine: intraobserver and interobserver reliability and the frequency of disagreement
Posterior spinal ligament pathology is becoming increasingly recognized as a significant cause of low back pain. Despite the growing clinical importance of interspinous ligament degeneration in low back pain patients, formal reliability studies for the magnetic resonance imaging (MRI) evaluation of interspinous ligaments have not been performed. We proposed an MRI classification system for interspinous ligament degeneration and conducted a comprehensive reliability and reproducibility assessment. Fifty patients who had low back pain with or without leg discomfort (26 males and 24 females) with a mean age of 48.8Â years (range 23â85Â years) were studied. The classification for lumbar interspinous ligament degeneration was developed on the basis of the literature using mid-sagittal T1- and T2-weighted images. Three spine surgeons independently graded a total of 200 interspinous ligament levels. Intraobserver and interobserver reliability were assessed by kappa statistics. The frequency of disagreement was also identified. The intraobserver agreement was excellent in all readers (kappa range 0.840â0.901). The interobserver agreement was lower as expected, and was substantial to excellent (kappa range 0.726â0.818). Overall complete agreement was obtained in 87.8% of all interspinous ligament levels. A difference of 1, 2, and 3 grades occurred in 8.1, 3.0, and 1.1% of readings, respectively. This proposed MRI classification of interspinous ligament degeneration was simple, reliable, and reproducible. Its use as a standardized nomenclature in clinical and radiographic research may be recommended
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