3,128 research outputs found
Preparation to the CMB PLANCK data analysis, estimation of the contamination due to the galactic polarized emissions
This work is point of the preparation to the analysis of the PLANCK satellite
data. The PLANCK satellite is an ESA mission which has been launched the 14th
of may 2009 and is dedicaced to the measurement of the Cosmic Microwave
Background (CMB) in temperature and polarization. The presence of diffuse
Galactic polarized emissions disturb the measurement of the CMB anisotropies,
in particular in polarization. Therefore a precise knowledge of these emissions
is needed to obtain the level of accuracy required for PLANCK. In this context,
we have developed and implemented a coherent 3D model of the two mains
polarized Galactic emissions : synchrotron and thermal dust. We have compared
these models to preexisting data: the 23 GHz band of the WMAP data, the 353 GHz
Archeops data and the 408 MHz all-sky continuum survey. We extrapolate these
models to the frequencies where the CMB dominates and we are able to estimate
the contribution of polarized foreground emissions to the polarized CMB
emission measured with PLANCK.Comment: Proceeding of the International Workshop on Cosmic Structure and
Evolution - Cosmology2009, September 23-25, 2009 Bielefeld, German
Constraining New Physics with D meson decays
Latest Lattice results on form factors evaluation from first principles
show that the standard model (SM) branching ratios prediction for the leptonic
decays and the semileptonic SM branching ratios of the
and meson decays are in good agreement with the world average
experimental measurements. It is possible to disprove New Physics hypothesis or
find bounds over several models beyond the SM. Using the observed leptonic and
semileptonic branching ratios for the D meson decays, we performed a combined
analysis to constrain non standard interactions which mediate the transition. This is done either by a model independent way through
the corresponding Wilson coefficients or in a model dependent way by finding
the respective bounds over the relevant parameters for some models beyond the
standard model. In particular, we obtain bounds for the Two Higgs Doublet Model
Type-II and Type III, the Left-Right model, the Minimal Supersymmetric Standard
Model with explicit R-Parity violation and Leptoquarks. Finally, we estimate
the transverse polarization of the lepton in the decay and we found it
can be as high as .Comment: 28 pages, 8 figures, 3 tables. Improved and extended analysis with
updated form factors from Lattice QC
Adaptation of a Leadership Training Program for Latinas
Involving community participants in the adaptation of culturally-specific programs has the potential to greatly enhance program fit, particularly for socio-politically distinct implementation sites. Findings from a case study of a leadership-training program for Latina survivors of domestic violence in Atlanta, GA support a participant-centered approach to program adaptation and evaluation. A summary of the adaptation process and themes from a qualitative analysis of structured interviews with program facilitators are presented. Implications for the leadership program and future research in the area of program adaptation are discussed
Quantum Stress Tensor Fluctuations and their Physical Effects
We summarize several aspects of recent work on quantum stress tensor
fluctuations and their role in driving fluctuations of the gravitational field.
The role of correlations and anticorrelations is emphasized. We begin with a
review of the properties of the stress tensor correlation function. We next
consider some illuminating examples of non-gravitational effects of stress
tensors fluctuations, specifically fluctuations of the Casimir force and
radiation pressure fluctuations. We next discuss passive fluctuations of
spacetime geometry and some of their operational signatures. These include
luminosity fluctuations, line broadening, and angular blurring of a source
viewed through a fluctuating gravitational field. Finally, we discuss the
possible role of quantum stress tensor fluctuations in the early universe,
especially in inflation. The fluctuations of the expansion of a congruence of
comoving geodesics grows during the inflationary era, due to non-cancellation
of anticorrelations that would have occurred in flat spacetime. This results in
subsequent non-Gaussian density perturbations and allows one to infer an upper
bound on the duration of inflation. This bound is consistent with adequate
inflation to solve the horizon and flatness problems.Comment: 15 pages, 1 figure; invited talk presented at the 3rd Mexican Meeting
on Experimental and Theoretical Physics, Mexico City, September 10-14, 200
The scalar sector in the Myers-Pospelov model
We construct a perturbative expansion of the scalar sector in the
Myers-Pospelov model, up to second order in the Lorentz violating parameter and
taking into account its higher-order time derivative character. This expansion
allows us to construct an hermitian positive-definite Hamiltonian which
provides a correct basis for quantization. Demanding that the modified normal
frequencies remain real requires the introduction of an upper bound in the
magnitude |k| of the momentum, which is a manifestation of the effective
character of the model. The free scalar propagator, including the corresponding
modified dispersion relations, is also calculated to the given order, thus
providing the starting point to consider radiative corrections when
interactions are introduced.Comment: Published in AIP Conf.Proc.977:214-223,200
Study of Materials and Adhesives for Superconducting Cable Feedthroughs
Powering superconducting magnets requires the use of cryogenic feedthroughs for the superconducting cables capable of withstanding severe thermal, mechanical and electrical operating conditions. Such feedthrough shall provide the continuity of the superconducting circuit while ensuring a hydraulic separation at cryogenic temperature. A study about the adhesive and polymers required for the production of thermal shock resistant feedthroughs is presented. The strength of the busbar to adhesive joints was first investigated by compression/shear tests as well as pin and collar tests performed with four epoxy adhesives. After the selection of the most appropriate adhesive, pin and collar tests were performed with four different polymers. Based on the results, a superconducting cable feedthrough for 6 busbars of 6 kA and 12 busbars of 120 A was constructed and successfully tested
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