7,245 research outputs found

    The CKM Paradigm: Implications of the Most Recent Results

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    The implications of the most recent experimental results in the B and K meson systems on the CKM paradigm are investigated by means of a global fit to the theoretical predictions of the Standard Model. We advocate the frequentist approach Rfit, which is implemented in the CKMFitter package. Within this approach, constraints on the CKM parameters and other quantities of interest are obtained, and extensions of the Standard Model are investigated.Comment: 9 pages, Talk given at the XXXVIIth Rencontres de Moriond, Electroweak Interactions and Unified Theories, Les Arcs, March 9-16 200

    CP Violation and the Absence of Second Class Currents in Charmless B Decays

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    The absence of second class currents together with the assumption of factorization for non-leptonic B decays provide new constraints on CP observables in decay B to a0(980)(to eta pi) pi. The kinematics of this decay do not allow interference between the oppositely charged resonances in the Dalitz plot as in B0 to rho(770)pi. Nonetheless, under the assumption of factorization,the a0pi two-body time-dependent isospin analysis leads to a more robust extraction of the angle alpha than in the rhopi isospin-pentagon analysis. The absence of second class currents might lead to enhanced direct CP violation and/or allows for a test of some assumptions made in the alpha analysis in other decays like B to a0rho, B to b1(1235)pi, B to a0 a0, B to eta(eta')pipi and B to b1 a0. The effects from non-factorizable contributions on the determination of alpha are estimated by means of a numerical study.Comment: 8 pages, 2 figures, Latex. Accepted for publication in Eur.Phys.J.

    Atomic coexistence of superconductivity and incommensurate magnetic order in the Ba(Fe1-xCox)2As2 pnictide

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    75As NMR and susceptiblity were measured in a Ba(Fe1-xCox)2As2 single crystal for x=6%. Nuclear Magnetic Resonance (NMR) spectra and relaxation rates allow to show that all Fe sites experience an incommensurate magnetic ordering below T=31K. Comparison with undoped compound allows to estimate a typical moment of 0.05 muB. Anisotropy of the NMR widths can be interpreted using a model of incommensurability with a wavevector (1/2-eps,0,l) with eps of the order of 0.04. Below TC=21.8K, a full volume superconductivity develops as shown by susceptibility and relaxation rate, and magnetic order remains unaffected, demonstrating coexistence of both states on each Fe site.Comment: 4 pages, 4 figure

    Context Aware Adaptable Applications - A global approach

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    Actual applications (mostly component based) requirements cannot be expressed without a ubiquitous and mobile part for end-users as well as for M2M applications (Machine to Machine). Such an evolution implies context management in order to evaluate the consequences of the mobility and corresponding mechanisms to adapt or to be adapted to the new environment. Applications are then qualified as context aware applications. This first part of this paper presents an overview of context and its management by application adaptation. This part starts by a definition and proposes a model for the context. It also presents various techniques to adapt applications to the context: from self-adaptation to supervised approached. The second part is an overview of architectures for adaptable applications. It focuses on platforms based solutions and shows information flows between application, platform and context. Finally it makes a synthesis proposition with a platform for adaptable context-aware applications called Kalimucho. Then we present implementations tools for software components and a dataflow models in order to implement the Kalimucho platform

    Proposed parametric cooling of bilayer cuprate superconductors by terahertz excitation

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    We propose and analyze a scheme for parametrically cooling bilayer cuprates based on the selective driving of a cc-axis vibrational mode. The scheme exploits the vibration as a transducer making the Josephson plasma frequencies time-dependent. We show how modulation at the difference frequency between the intra- and interbilayer plasmon substantially suppresses interbilayer phase fluctuations, responsible for switching cc-axis transport from a superconducting to resistive state. Our calculations indicate that this may provide a viable mechanism for stabilizing non-equilibrium superconductivity even above TcT_c, provided a finite pair density survives between the bilayers out of equilibrium.Comment: 4 pages + 7 page supplementa

    Proposed cavity Josephson plasmonics with complex-oxide heterostructures

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    We discuss how complex-oxide heterostructures that include high-Tc superconducting cuprates can be used to realize an array of sub-millimeter cavities that support Josephson plasmon polaritons. These cavities have several attractive features for new types of light matter interaction studies and we show that they promote "ultrastrong" coupling between THz frequency radiation and Josephson plasmons. Cavity electrodynamics of Josephson plasmons allows to manipulate the superconducting order-parameter phase coherence. As an example, we discuss how it could be used to cool superconducting phase fluctuations with light

    Le bal des voleurs : apothéose ou métamorphose de la comédie-ballet ?

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    Pourquoi renouer, en plein XXe siècle, avec la comédie-ballet ? L’admiration d’Anouilh pour Molière n’explique pas tout. Le bal des voleurs cherche-t-il à ressusciter un genre disparu, ou plutôt à se démarquer du prestigieux modèle qu’il convoque ? Les deux options sont loin de s’exclure, dans une pièce traversée par une puissante dynamique chorégraphique. Si le bal annoncé par le titre n’a pas lieu, c’est peut-être que la pièce tout entière vise à se transformer en ballet.Why, one wonders, get reacquainted with comédie-ballet in the 1900s? Anouilh’s admiration for Molière is not the only explanation here. Could Le bal des voleurs be an attempt to rekindle a lost genre, or does it seek instead to distance itself from its prestigious inspiration? Both options are far from mutually exclusive throughout a play underpinned by potent choreography. As to the lack of the titular ball, could it be that the entire play seeks to pass itself off as a ballet

    Active Mass Under Pressure

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    After a historical introduction to Poisson's equation for Newtonian gravity, its analog for static gravitational fields in Einstein's theory is reviewed. It appears that the pressure contribution to the active mass density in Einstein's theory might also be noticeable at the Newtonian level. A form of its surprising appearance, first noticed by Richard Chase Tolman, was discussed half a century ago in the Hamburg Relativity Seminar and is resolved here.Comment: 28 pages, 4 figure
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