SearchCal: a Virtual Observatory tool for searching calibrators in optical long baseline interferometry. I: The bright object case

In long baseline interferometry, the raw fringe contrast must be calibrated to obtain the true visibility and then those observables that can be interpreted in terms of astrophysical parameters. The selection of suitable calibration stars is crucial for obtaining the ultimate precision of interferometric instruments like the VLTI. We have developed software SearchCal that builds an evolutive catalog of stars suitable as calibrators within any given user-defined angular distance and magnitude around the scientific target. We present the first version of SearchCal dedicated to the bright-object case V<=10; K<=5). Star catalogs available at the CDS are consulted via web requests. They provide all the useful information for selecting of calibrators. Missing photometries are computed with an accuracy of 0.1 mag and the missing angular diameters are calculated with a precision better than 10%. For each star the squared visibility is computed by taking the wavelength and the maximum baseline of the foreseen observation into account.} SearchCal is integrated into ASPRO, the interferometric observing preparation software developed by the JMMC, available at the address: http://mariotti.fr

Quenched Chiral Perturbation Theory for Vector Mesons

We develop quenched chiral perturbation theory for vector mesons made of light quarks, in the limit where the vector meson masses are much larger than the pion mass. We use this theory to extract the leading nonanalytic dependence of the vector meson masses on the masses of the light quarks. By comparing with analogous quantities computed in ordinary chiral perturbation theory, we estimate the size of quenching effects, observing that in general they can be quite large. This estimate is relevant to lattice simulations, where the $\rho$ mass is often used to set the lattice spacing.Comment: 18 pages, 8 figures, uses REVTeX and epsf.st

Modeling the strangeness content of hadronic matter

The strangeness content of hadronic matter is studied in a string-flip model that reproduces various aspects of the QCD-inspired phenomenology, such as quark clustering at low density and color deconfinement at high density, while avoiding long range van der Waals forces. Hadronic matter is modeled in terms of its quark constituents by taking into account its internal flavor (u,d,s) and color (red, blue, green) degrees of freedom. Variational Monte-Carlo simulations in three spatial dimensions are performed for the ground-state energy of the system. The onset of the transition to strange matter is found to be influenced by weak, yet not negligible, clustering correlations. The phase diagram of the system displays an interesting structure containing both continuous and discontinuous phase transitions. Strange matter is found to be absolutely stable in the model.Comment: 14 pages, 1 table, 8 eps figures, revtex. Submitted to Phys. Rev. C, Presented at INPC2001 Berkeley, Ca. july 29-Aug

Enhancement of the superconducting transition temperature from the competition between electron-electron correlations and electron-phonon interactions

We uncover that the competition between electron-electron correlations and electron-phonon interactions gives rise to unexpectedly huge enhancement of the superconducting transition temperature, several hundreds percent larger ($\geq$ 200 K) than that of the case when only one of the two is taken into account ($\sim$ 30 K). Our renormalization group analysis claims that this mechanism for the enhancement of the critical temperature is not limited on superconductivity but applied to various Fermi surface instabilities, proposing an underlying universal structure, which turns out to be essentially identical to that of a recent study [Phys. Rev. Lett. {\bf 108}, 046601 (2012)] on the enhancement of the Kondo temperature in the presence of Rashba spin-orbit interactions. We also discuss the stability of superconductivity against nonmagnetic randomness

Tevatron-for-LHC Report: Preparations for Discoveries

This is the "TeV4LHC" report of the "Physics Landscapes" Working Group, focused on facilitating the start-up of physics explorations at the LHC by using the experience gained at the Tevatron. We present experimental and theoretical results that can be employed to probe various scenarios for physics beyond the Standard Model.Comment: 222 pp., additional contribution added, typos/layout correcte

B --> pi and B --> K transitions in partially quenched chiral perturbation theory

We study the properties of the B-->pi and B-->K transition form factors in partially quenched QCD by using the approach of partially quenched chiral perturbation theory combined with the static heavy quark limit. We show that the form factors change almost linearly when varying the value of the sea quark mass, whereas the dependence on the valence quark mass contains both the standard and chirally divergent (quenched) logarithms. A simple strategy for the chiral extrapolations in the lattice studies with Nsea=2 is suggested. It consists of the linear extrapolations from the realistically accessible quark masses, first in the sea and then in the valence quark mass. From the present approach, we estimate the uncertainty induced by such extrapolations to be within 5%.Comment: Published versio

PIONIER: a visitor instrument for the VLTI

PIONIER is a 4-telescope visitor instrument for the VLTI, planned to see its first fringes in 2010. It combines four ATs or four UTs using a pairwise ABCD integrated optics combiner that can also be used in scanning mode. It provides low spectral resolution in H and K band. PIONIER is designed for imaging with a specific emphasis on fast fringe recording to allow closure-phases and visibilities to be precisely measured. In this work we provide the detailed description of the instrument and present its updated status.Comment: Proceedings of SPIE conference Optical and Infrared Interferometry II (Conference 7734) San Diego 201

Development of a Compton camera for medical applications based on silicon strip and scintillation detectors

International audienceA Compton camera is being developed for the purpose of ion-range monitoring during hadrontherapy via the detection of prompt-gamma rays. The system consists of a scintillating fiber beam tagging hodoscope, a stack of double sided silicon strip detectors (90 Â 90 Â 2 mm 3 , 2 Â 64 strips) as scatter detectors, as well as bismuth germanate (BGO) scintillation detectors (38 Â 35 Â 30 mm 3 , 100 blocks) as absorbers. The individual components will be described, together with the status of their characterization

Numerical analysis of seepage–deformation in unsaturated soils

A coupled elastic–plastic finite element analysis based on simplified consolidation theory for unsaturated soils is used to investigate the coupling processes of water infiltration and deformation. By introducing a reduced suction and an elastic–plastic constitutive equation for the soil skeleton, the simplified consolidation theory for unsaturated soils is incorporated into an in-house finite element code. Using the proposed numerical method, the generation of pore water pressure and development of deformation can be simulated under evaporation or rainfall infiltration conditions. Through a parametric study and comparison with the test results, the proposed method is found to describe well the characteristics during water evaporation/infiltration into unsaturated soils. Finally, an unsaturated soil slope with water infiltration is analyzed in detail to investigate the development of the displacement and generation of pore water pressure