3,070 research outputs found

    Preparation to the CMB PLANCK data analysis, estimation of the contamination due to the galactic polarized emissions

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    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

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    Latest Lattice results on DD form factors evaluation from first principles show that the standard model (SM) branching ratios prediction for the leptonic Ds→ℓνℓD_s \to \ell \nu_\ell decays and the semileptonic SM branching ratios of the D0D^0 and D+D^+ 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 csˉ→lνˉc\bar{s}\to l\bar{\nu} 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 D0D^0 decay and we found it can be as high as PT=0.23P_T=0.23.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

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    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

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    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

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    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

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    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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