754 research outputs found
Radiative CP Phases in Supergravity Theories
In this letter, we point out that possible sources of CP violation originate
from radiative corrections to soft terms which are ubiquitous in supergravity
theories and also in other high-energy frameworks of supersymmetry breaking.
With these radiative phases of gaugino masses and scalar couplings, a complex
phase of Higgs holomorphic mass parameter is generated via
renormalization-group running down to low energy. It is found that its phase
value is mainly controlled by wino as well as gluino, which generally receive
different radiative corrections to their complex phases, even if the leading
part of mass parameters follow from the universality hypothesis. The
radiatively generated phases are constrained by the existing experimental
bounds on electric dipole moments, and may be detectable in future
measurements. They are also found to be available for the cancellation
mechanism to be worked.Comment: 14 pages, 5 figures, references adde
Phenomenology of Minimal Supergravity with Vanishing A and B Soft Supersymmetry-Breaking Parameters
The ansatz of vanishing A and B parameters eliminates CP violating complex
phases in soft supersymmetry-breaking parameters of the minimal supersymmetric
standard model, and thus provides a simple solution to the supersymmetry CP
problem. Phenomenological implications of this ansatz are investigated in the
framework of minimal supergravity. We show that electroweak symmetry breakdown
occurs, predicting relatively large \tan \beta. The ansatz survives the Higgs
mass bound as well as the b \to s \gamma constraint if the universal gaugino
mass is larger than 300 GeV. We also find that the supersymmetric contribution
to the anomalous magnetic moment of muon lies in an experimentally interesting
region of order 10^{-9} in a large portion of the parameter space.Comment: 6 pages, 3 figure
Bottom-Up Approach to Moduli Dynamics in Heavy Gravitino Scenario : Superpotential, Soft Terms and Sparticle Mass Spectrum
The physics of moduli fields is examined in the scenario where the gravitino
is relatively heavy with mass of order 10 TeV, which is favored in view of the
severe gravitino problem. The form of the moduli superpotential is shown to be
determined, if one imposes a phenomenological requirement that no physical CP
phase arise in gaugino masses from conformal anomaly mediation. This bottom-up
approach allows only two types of superpotential, each of which can have its
origins in a fundamental underlying theory such as superstring. One
superpotential is the sum of an exponential and a constant, which is identical
to that obtained by Kachru et al (KKLT), and the other is the racetrack
superpotential with two exponentials. The general form of soft supersymmetry
breaking masses is derived, and the pattern of the superparticle mass spectrum
in the minimal supersymmetric standard model is discussed with the KKLT-type
superpotential. It is shown that the moduli mediation and the anomaly mediation
make comparable contributions to the soft masses. At the weak scale, the
gaugino masses are rather degenerate compared to the minimal supergravity,
which bring characteristic features on the superparticle masses. In particular,
the lightest neutralino, which often constitutes the lightest superparticle and
thus a dark matter candidate, is a considerable admixture of gauginos and
higgsinos. We also find a small mass hierarchy among the moduli, gravitino, and
superpartners of the standard-model fields. Cosmological implications of the
scenario are briefly described.Comment: 45 pages, 10 figures, typos correcte
Anomalous Hall voltage rectification and quantized spin-wave excitation induced by the simultaneous dc- and rf-current application in Ni81Fe19 wire
An anomalous Hall effect and rectification of a Hall voltage are observed by
applying a radio-frequency (rf) current through a single-layered ferromagnetic
wire located on a coplanar waveguide. The components of the magnetization
precession, both in and perpendicular to the plane, can be detected via the
Hall voltage rectification of the rf current by incorporating an additional
direct (dc) current. In this paper, we propose a phenomenological model, which
describes the time-dependent anisotropic magnetoresistance and time-dependent
planer Hall effect. The nonlinearity of the spin dynamics accompanied by
spin-waves as functions of rf and dc currents is also studied, as well as those
of the magnitude and orientation of the external magnetic field.Comment: 42 pages, 5 figures, submitte
Broadband ferromagnetic resonance of Ni81Fe19 wires using a rectifying effect
The broadband ferromagnetic resonance measurement using the rectifying effect
of Ni81Fe19 wire has been investigated. One wire is deposited on the center
strip line of the coplanar waveguide (CPW) and the other one deposited between
two strip lines of CPW. The method is based on the detection of the
magnetoresistance oscillation due to the magnetization dynamics induced by the
radio frequency field. The magnetic field dependences of the resonance
frequency and the rectification spectrum are presented and analytically
interpreted on the standpoint of a uniform magnetization precession model.Comment: 33pages, 8 figures. submitte
Primary T-cell Lymphoma of the Thyroid Associated with Hashimoto's Thyroiditis, Histologically Mimicking MALT-Lymphoma
Most of thyroid lymphomas are B-lineage, and T-cell lymphomas are rare. Here, we report a case of primary thyroid T-cell lymphoma associated with Hashimoto's thyroiditis. A 48-yr-old woman presented with incidentally found neck mass. Histologically, the resected right lobe of the thyroid was replaced by monomorphic small atypical lymphoid cells with lymphoepithelial lesion-like change, most of which were immunoreactive for CD3, CD8, βF-1, and TIA-1. Peripheral T-cell lymphoma, unspecified, was finally diagnosed after molecular study for TCR-γ gene rearrangement. This is the second case of cytotoxic T-cell lymphoma reported in the thyroid gland so far. Unique association between thyroid follicles and neoplastic lymphocytes may be characteristic feature of this type of T-cell lymphoma
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