1,965 research outputs found
Baryon Stability on the Higgs Dissolution Edge : Threshold corrections and suppression of Baryon violation in the NMSGUT
Superheavy threshold corrections to the matching condition between matter
Yukawa couplings of the effective Minimal Supersymmetric Standard Model (MSSM)
and the New Minimal Supersymmetric (SO(10)) GUT(NMSGUT) provide a novel and
generic mechanism for reducing the long standing and generically problematic
operator dimension 5 Baryon decay rates. In suitable regions of the parameter
space strong wave function renormalization of the effective MSSM Higgs doublets
due to the large number of heavy fields can take the wave function
renormalization of the MSSM Higgs field close to the dissolution value
(). Rescaling to canonical kinetic terms lowers the
SO(10) Yukawas required to match the MSSM fermion data. Since the same Yukawas
determine the dimension 5 B violation operator coefficients, the associated
rates can be suppressed to levels compatible with current limits. Including
these threshold effects also relaxes the constraint operative between plet generated tree
level MSSM matter fermion Yukawas . We exhibit accurate fits of the MSSM
fermion mass-mixing data in terms of NMSGUT superpotential couplings and 5
independent soft Susy breaking parameters specified at GeV with
the claimed suppression of Baryon decay rates. As before, our s-spectra are of
the mini split supersymmetry type with large TeV, light gauginos and normal s-hierarchy. Large and soft
masses allow significant deviation from the canonical GUT gaugino mass ratios
and ensure vacuum safety. Even without optimization, prominent candidates for
BSM discovery such as the muon magnetic anomaly, and
Lepto-genesis CP violation emerge in the preferred ball park.Comment: PdfLatex. 50 pages. Version accepted for publication in Nuclear
Phys.B(2014). Available online at
http://dx.doi.org/10.1016/j.nuclphysb.2014.03.003. arXiv admin note:
substantial text overlap with arXiv:1107.296
Photoionization in the time and frequency domain
Ultrafast processes in matter, such as the electron emission following light
absorption, can now be studied using ultrashort light pulses of attosecond
duration (s) in the extreme ultraviolet spectral range. The lack of
spectral resolution due to the use of short light pulses may raise serious
issues in the interpretation of the experimental results and the comparison
with detailed theoretical calculations. Here, we determine photoionization time
delays in neon atoms over a 40 eV energy range with an interferometric
technique combining high temporal and spectral resolution. We spectrally
disentangle direct ionization from ionization with shake up, where a second
electron is left in an excited state, thus obtaining excellent agreement with
theoretical calculations and thereby solving a puzzle raised by seven-year-old
measurements. Our experimental approach does not have conceptual limits,
allowing us to foresee, with the help of upcoming laser technology, ultra-high
resolution time-frequency studies from the visible to the x-ray range.Comment: 5 pages, 4 figure
Modal analysis using a Fourier analyzer, curve-fitting, and modal tuning
The proposed modal test program differs from single-input methods in that preliminary data may be acquired using multiple inputs, and modal tuning procedures may be employed to define closely spaced frquency modes more accurately or to make use of frequency response functions (FRF's) which are based on several input locations. In some respects the proposed modal test proram resembles earlier sine-sweep and sine-dwell testing in that broadband FRF's are acquired using several input locations, and tuning is employed to refine the modal parameter estimates. The major tasks performed in the proposed modal test program are outlined. Data acquisition and FFT processing, curve fitting, and modal tuning phases are described and examples are given to illustrate and evaluate them
Investigation of organic adhesives for hybrid microcircuits
The properties of organic adhesives were investigated to acquire information for a guideline document regarding the selection of adhesives for use in high reliability hybrid microcircuits. Specifically, investigations were made of (1) alternate methods for determining the outgassing of cured adhesives, (2) effects of long term aging at 150 C on the electrical properties of conductive adhesives, (3) effects of shelf life age on adhesive characteristics, (4) bond strengths of electrically conductive adhesives on thick film gold metallization, (5) a copper filled adhesive, (6) effects of products outgassed from cured adhesives on device electrical parameters, (7) metal migration from electrically conductive adhesives, and (8) ionic content of electrically insulative adhesives. The tests performed during these investigations are described, and the results obtained are discussed
High harmonic generation from Bloch electrons in solids
We study the generation of high harmonic radiation by Bloch electrons in a
model transparent solid driven by a strong mid-infrared laser field. We solve
the single-electron time-dependent Schr\"odinger equation (TDSE) using a
velocity-gauge method [New J. Phys. 15, 013006 (2013)] that is numerically
stable as the laser intensity and number of energy bands are increased. The
resulting harmonic spectrum exhibits a primary plateau due to the coupling of
the valence band to the first conduction band, with a cutoff energy that scales
linearly with field strength and laser wavelength. We also find a weaker second
plateau due to coupling to higher-lying conduction bands, with a cutoff that is
also approximately linear in the field strength. To facilitate the analysis of
the time-frequency characteristics of the emitted harmonics, we also solve the
TDSE in a time-dependent basis set, the Houston states [Phys. Rev. B 33, 5494
(1986)], which allows us to separate inter-band and intra-band contributions to
the time-dependent current. We find that the inter-band and intra-band
contributions display very different time-frequency characteristics. We show
that solutions in these two bases are equivalent under an unitary
transformation but that, unlike the velocity gauge method, the Houston state
treatment is numerically unstable when more than a few low lying energy bands
are used
On cross-diffusion systemsfor two populations subject to a common congestion effect
In this paper, we investigate the existence of solution for systems of
Fokker-Planck equations coupled through a common nonlinear congestion. Two
different kinds of congestion are considered: a porous media congestion or
\textit{soft} congestion and the \textit{hard} congestion given by the
constraint . We show that these systems can be seen
as gradient flows in a Wasserstein product space and then we obtain a
constructive method to prove the existence of solutions. Therefore it is
natural to apply it for numerical purposes and some numerical simulations are
included
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