1,176 research outputs found

    The SUSY flavor problem in 5D GUTs

    Full text link
    In 5D SUSY GUTs, wave-function localization permits to reproduce flavour hierarchy. As this mechanism also acts on SUSY breaking parameters, it can potentially solve the SUSY flavour problem. We carry out an analysis of the Holographic Grand Unification framework, where we take properly into account effects of matrix anarchy. In this contribution, we focus on brane-localized SUSY breaking and its consequences.Comment: Prepared for the proceedings of the Moriond 2011 EW session. 4 pages, 7 figure

    Probing new physics in diphoton production with proton tagging at the Large Hadron Collider

    Get PDF
    The sensitivities to anomalous quartic photon couplings at the Large Hadron Collider are estimated using diphoton production via photon fusion. The tagging of the protons proves to be a very powerful tool to suppress the background and unprecedented sensitivities down to 610156 \cdot 10^{-15}\gev4^{-4} are obtained, providing a new window on extra dimensions and strongly-interacting composite states in the multi-TeV range. Generic contributions to quartic photon couplings from charged and neutral particles with arbitrary spin are also presented.Comment: 4 pages, 3 figure

    Saturation effects in the sub-Doppler spectroscopy of Cesium vapor confined in an Extremely Thin Cell

    Full text link
    Saturation effects affecting absorption and fluorescence spectra of an atomic vapor confined in an Extremely Thin Cell (cell thickness L<1μmL < 1 \mu m) are investigated experimentally and theoretically. The study is performed on the D2D_{2} line (λ = 852nm)\lambda ~= ~852 nm) of CsCs and concentrates on the two situations L=λ/2L = \lambda /2 and L=λL =\lambda, the most contrasted ones with respect to the length dependence of the coherent Dicke narrowing. For L=λ/2L = \lambda /2, the Dicke-narrowed absorption profile simply broadens and saturates in amplitude when increasing the light intensity, while for L=λL =\lambda, sub-Doppler dips of reduced absorption at line-center appear on the broad absorption profile. For a fluorescence detection at L=λL =\lambda, saturation induces narrow dips, but only for hyperfine components undergoing a population loss through optical pumping. These experimental results are interpreted with the help of the various existing models, and are compared with numerical calculations based upon a two-level modelling that considers both a closed and an open system.Comment: 11 pages, 12 figure

    Programmable logic circuits for functional integrated smart plastic systems

    Get PDF
    In this paper, we present a functional integrated plastic system. We have fabricated arrays of organic thin-film transistors (OTFTs) and printed electronic components driving an electrophoretic ink display up to 70 mm by 70 mm on a single flexible transparent plastic foil. Transistor arrays were quickly and reliably configured for different logic functions by an additional process step of inkjet printing conductive silver wires and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) resistors between transistors or between logic blocks. Among the circuit functions and features demonstrated on the arrays are a 7-stage ring oscillator, a D-type flip-flop memory element, a 2:4 demultiplexer, a programmable array logic device (PAL), and printed wires and resistors. Touch input sensors were also printed, thus only external batteries were required for a complete electronic subsystem. The PAL featured 8 inputs, 8 outputs, 32 product terms, and had 1260 p-type polymer transistors in a 3-metal process using diode-load logic. To the best of our knowledge, this is the first time that a PAL concept with organic transistors has been demonstrated, and also the first time that organic transistors have been used as the control logic for a flexible display which have both been integrated on to a single plastic substrate. The versatility afforded by the additive inkjet printing process is well suited to organic programmable logic on plastic substrates, in effect, making flexible organic electronics more flexible. Crown Copyright (C) 2014 Published by Elsevier B.V.X113426Ysciescopu

    Setting limits on Effective Field Theories: the case of Dark Matter

    Full text link
    The usage of Effective Field Theories (EFT) for LHC new physics searches is receiving increasing attention. It is thus important to clarify all the aspects related with the applicability of the EFT formalism in the LHC environment, where the large available energy can produce reactions that overcome the maximal range of validity, i.e. the cutoff, of the theory. We show that this does forbid to set rigorous limits on the EFT parameter space through a modified version of the ordinary binned likelihood hypothesis test, which we design and validate. Our limit-setting strategy can be carried on in its full-fledged form by the LHC experimental collaborations, or performed externally to the collaborations, through the Simplified Likelihood approach, by relying on certain approximations. We apply it to the recent CMS mono-jet analysis and derive limits on a Dark Matter (DM) EFT model. DM is selected as a case study because the limited reach on the DM production EFT Wilson coefficient and the structure of the theory suggests that the cutoff might be dangerously low, well within the LHC reach. However our strategy can also be applied to EFT's parametrising the indirect effects of heavy new physics in the Electroweak and Higgs sectors

    Towards surface quantum optics with Bose-Einstein condensates in evanescent waves

    Full text link
    We present a surface trap which allows for studying the coherent interaction of ultracold atoms with evanescent waves. The trap combines a magnetic Joffe trap with a repulsive evanescent dipole potential. The position of the magnetic trap can be controlled with high precision which makes it possible to move ultracold atoms to the surface of a glass prism in a controlled way. The optical potential of the evanescent wave compensates for the strong attractive van der Waals forces and generates a potential barrier at only a few hundred nanometers from the surface. The trap is tested with Rb Bose-Einstein condensates (BEC), which are stably positioned at distances from the surfaces below one micrometer

    High contrast D1_{1} line electromagnetically induced transparency in nanometric-thin rubidium vapor cell

    Full text link
    Electromagnetically induced transparency (EIT) on atomic D1_{1} line of rubidium is studied using a nanometric-thin cell with atomic vapor column length in the range of L= 400 - 800 nm. It is shown that the reduction of the cell thickness by 4 orders as compared with an ordinary cm-size cell still allows to form an EIT resonance for L=λL= \lambda (λ=794\lambda =794 nm) with the contrast of up to 40%. Remarkable distinctions of EIT formation in nanometric-thin and ordinary cells are demonstrated. Despite the Dicke effect of strong spectral narrowing and increase of the absorption for L=L= λ/2\lambda /2, EIT resonance is observed both in the absorption and the fluorescence spectra for relatively low intensity of the coupling laser. Well resolved splitting of the EIT resonance in moderate magnetic field for L=L= λ\lambda can be used for magnetometry with nanometric spatial resolution. The presented theoretical model well describes the observed results.Comment: Submitted to Applied Physics B: Lasers and Optics, 9 pages, 10 figure

    On SUSY GUTs with a degenerate Higgs mass matrix

    Get PDF
    Certain supersymmetric grand unified models predict that the coefficients of the quadratic terms in the MSSM Higgs potential should be degenerate at the GUT scale. We discuss some examples for such models, and we analyse the implications of this peculiar condition of a GUT-scale degenerate Higgs mass matrix for low-scale MSSM phenomenology. To this end we explore the parameter space which is consistent with existing experimental constraints by means of a Markov Chain Monte Carlo analysis.Comment: 31 pages, 27 figures; v2: typos correcte

    Using atomic interference to probe atom-surface interaction

    Get PDF
    We show that atomic interference in the reflection from two suitably polarized evanescent waves is sensitive to retardation effects in the atom-surface interaction for specific experimental parameters. We study the limit of short and long atomic de Broglie wavelength. The former case is analyzed in the semiclassical approximation (Landau-Zener model). The latter represents a quantum regime and is analyzed by solving numerically the associated coupled Schroedinger equations. We consider a specific experimental scheme and show the results for rubidium (short wavelength) and the much lighter meta-stable helium atom (long wavelength). The merits of each case are then discussed.Comment: 11 pages, including 6 figures, submitted to Phys. Rev. A, RevTeX sourc

    A Unified Framework for the Infection Dynamics of Zoonotic Spillover and Spread.

    Get PDF
    A considerable amount of disease is transmitted from animals to humans and many of these zoonoses are neglected tropical diseases. As outbreaks of SARS, avian influenza and Ebola have demonstrated, however, zoonotic diseases are serious threats to global public health and are not just problems confined to remote regions. There are two fundamental, and poorly studied, stages of zoonotic disease emergence: 'spillover', i.e. transmission of pathogens from animals to humans, and 'stuttering transmission', i.e. when limited human-to-human infections occur, leading to self-limiting chains of transmission. We developed a transparent, theoretical framework, based on a generalization of Poisson processes with memory of past human infections, that unifies these stages. Once we have quantified pathogen dynamics in the reservoir, with some knowledge of the mechanism of contact, the approach provides a tool to estimate the likelihood of spillover events. Comparisons with independent agent-based models demonstrates the ability of the framework to correctly estimate the relative contributions of human-to-human vs animal transmission. As an illustrative example, we applied our model to Lassa fever, a rodent-borne, viral haemorrhagic disease common in West Africa, for which data on human outbreaks were available. The approach developed here is general and applicable to a range of zoonoses. This kind of methodology is of crucial importance for the scientific, medical and public health communities working at the interface between animal and human diseases to assess the risk associated with the disease and to plan intervention and appropriate control measures. The Lassa case study revealed important knowledge gaps, and opportunities, arising from limited knowledge of the temporal patterns in reporting, abundance of and infection prevalence in, the host reservoir.Natural Environment Research Council (project no.: NEJ001570-1), Department for International Development, Economic and Social Research Council, National Institute for Health Research, Science and Technology Directorate, Department of Homeland Security, Fogarty International Center USA, European Union FP7 (project ANTIGONE (contract number 278976)), Royal Society (Wolfson Research Merit Award), Alborada Trust, US National Institute of Health (P20GM103501, BAANIAID-DAIT-NIHQI2008031, HHSN272201000022C, HHSN272200900049C, 1U19AI109762, 1R01AI104621, 2R44AI088843), USAID/NIH PEER Health grant.This is the final version of the article. It first appeared from the Public Library of Science via http://dx.doi.org/10.1371/journal.pntd.000495
    corecore