5,745 research outputs found
Complete structure of Z_n Yukawa couplings
We give the complete twisted Yukawa couplings for all the Z_n orbifold
constructions in the most general case, i.e. when orbifold deformations are
considered. This includes a certain number of tasks. Namely, determination of
the allowed couplings, calculation of the explicit dependence of the Yukawa
couplings values on the moduli expectation values (i.e. the parameters
determining the size and shape of the compactified space), etc. The final
expressions are completely explicit, which allows a counting of the DIFFERENT
Yukawa couplings for each orbifold (with and without deformations). This
knowledge is crucial to determine the phenomenological viability of the
different schemes, since it is directly related to the fermion mass hierarchy.
Other facts concerning the phenomenological profile of Z_n orbifolds are also
discussed, e.g. the existence of non--diagonal entries in the fermion mass
matrices, which is related to a non--trivial structure of the
Kobayashi--Maskawa matrix. Finally some theoretical results are given, e.g. the
no--participation of (1,2) moduli in twisted Yukawa couplings. Likewise, (1,1)
moduli associated with fixed tori which are involved in the Yukawa coupling, do
not affect the value of the coupling.Comment: 60 page
A modular radiative transfer program for gas filter correlation radiometry
The fundamentals of a computer program, simulated monochromatic atmospheric radiative transfer (SMART), which calculates atmospheric path transmission, solar radiation, and thermal radiation in the 4.6 micrometer spectral region, are described. A brief outline of atmospheric absorption properties and line by line transmission calculations is explained in conjunction with an outline of the SMART computational procedures. Program flexibility is demonstrated by simulating the response of a gas filter correlation radiometer as one example of an atmospheric infrared sensor. Program limitations, input data requirements, program listing, and comparison of SMART transmission calculations are presented
Data reduction analysis and application technique development for atmospheric trace gas constituents derived from remote sensors on satellite or airborne platforms
The applicability of the gas filter correlation radiometer (GFCR) to the measurement of tropospheric carbon monoxide gas was investigated. An assessment of the GFRC measurement system to a regional measurement program was conducted through extensive aircraft flight-testing of several versions of the GFRC. Investigative work in the following areas is described: flight test planning and coordination, acquisition of verifying CO measurements, determination and acquisition of supporting meteorological data requirements, and development of supporting computational software
SUSY Soft Breaking Terms from String Scenarios
The general SUSY soft breaking terms for a large class of phenomenologically
relevant string scenarios (symmetric orbifolds) are given. They show a certain
lack of universality, but not dangerous for flavor changing neutral currents.
To get more quantitative results a specific SUSY breaking mechanism has to be
considered, namely gaugino condensation in the hidden sector. Then, it turns
out that squark and slepton masses tend to be much larger than scalar masses
(), which probably is a quite general fact. Experimental
bounds and the requirement of a successful electroweak breaking without fine
tuning impose further restrictions on the soft breaking terms. As a consequence
the gluino and chargino masses should be quite close to their present
experimental limits, whereas squark and slepton masses should be much higher (>
1 TeV).Comment: (Talk presented at the SUSY-93 Conference, Boston, March 29 - April
2, 1993), 11 pages, CERN--TH.6922/9
Three field tests of a gas filter correlation radiometer
Test flights to remotely measure nonurban carbon monoxide (CO) concentrations by gas filter correlation radiometry are discussed. The inferred CO concentrations obtained through use of the Gas Filter Correlation Radiometer (GFCR) agreed with independent measurements obtained by gas chromatography air sample bottle analysis to within 20 percent. The equipment flown on board the aircraft, the flight test procedure, the gas chromatograph direct air sampling procedure, and the GFCR data analysis procedure are reported
Instrumentation status of the low-b magnet systems at the Large Hadron Collider (LHC)
The low-beta magnet systems are located in the Large Hadron Collider (LHC)
insertion regions around the four interaction points. They are the key elements
in the beams focusing/defocusing process allowing proton collisions at
luminosity up to 10**34/cm**2s. Those systems are a contribution of the US-LHC
Accelerator project. The systems are mainly composed of the quadrupole magnets
(triplets), the separation dipoles and their respective electrical feed-boxes
(DFBX). The low-beta magnet systems operate in an environment of extreme
radiation, high gradient magnetic field and high heat load to the cryogenic
system due to the beam dynamic effect. Due to the severe environment, the
robustness of the diagnostics is primordial for the operation of the triplets.
The hardware commissioning phase of the LHC was completed in February 2010. In
the sake of a safer and more user-friendly operation, several consolidations
and instrumentation modifications were implemented during this commissioning
phase. This paper presents the instrumentation used to optimize the engineering
process and operation of the final focusing/defocusing quadrupole magnets for
the first years of operation.Comment: 6 pp. ICEC 23 - ICMC 2010 International Cryogenic Engineering
Conference 23 - International Cryogenic Materials Conference 2010. 19-23 Jul
2010. Wroclaw, Polan
Optimal Control of the Thermistor Problem in Three Spatial Dimensions
This paper is concerned with the state-constrained optimal control of the
three-dimensional thermistor problem, a fully quasilinear coupled system of a
parabolic and elliptic PDE with mixed boundary conditions. This system models
the heating of a conducting material by means of direct current. Local
existence, uniqueness and continuity for the state system are derived by
employing maximal parabolic regularity in the fundamental theorem of Pr\"uss.
Global solutions are addressed, which includes analysis of the linearized state
system via maximal parabolic regularity, and existence of optimal controls is
shown if the temperature gradient is under control. The adjoint system
involving measures is investigated using a duality argument. These results
allow to derive first-order necessary conditions for the optimal control
problem in form of a qualified optimality system. The theoretical findings are
illustrated by numerical results
Bounds on the Higgs-Boson Mass in the Presence of Non-Standard Interactions
The triviality and vacuum stability bounds on the Higgs-boson mass are
revisited in the presence of new interactions parameterized in a
model-independent way by an effective lagrangian. When the scale of new physics
is below 50 TeV the triviality bound is unchanged but the stability lower bound
is increased by 40-60 GeV. Should the Higgs-boson mass be close to its current
lower experimental limit, this leads to the possibility of new physics at the
scale of a few TeV, even for modest values of the effective lagrangian
parameters.Comment: 5 pages, 2 figures, RevTex, submitted to PR
The role of rotation on Petersen Diagrams. II The influence of near-degeneracy
In the present work, the effect of near-degeneracy on rotational Petersen
diagrams (RPD) is analysed. Seismic models are computed considering rotation
effects on both equilibrium models and adiabatic oscillation frequencies
(including second-order near-degeneracy effects). Contamination of coupled
modes and coupling strength on the first radial modes are studied in detail.
Analysis of relative intrinsic amplitudes of near-degenerate modes reveals that
the identity of the fundamental radial mode and its coupled quadrupole pair are
almost unaltered once near-degeneracy effects are considered. However, for the
first overtone, a mixed radial/quadrupole identity is always predicted. The
effect of near-degeneracy on the oscillation frequencies becomes critical for
rotational velocities larger than 15-20 km/s, for which large wriggles in the
evolution of the period ratios are obtained (up ). Such wriggles imply
uncertainties, in terms of metallicity determinations using RPD, reaching up to
0.50 dex, which can be critical for Pop. I HADS (High Amplitude \dss). In terms
of mass determinations, uncertainties reaching up to 0.5 M_sun are predicted.
The location of such wriggles is found to be independent of metallicity and
rotational velocity, and governed mainly by the avoided-crossing phenomenon.Comment: 8 pages, 7 figures, 1 table. (accepted for publication in A&A
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