17,266 research outputs found

    Solving the Hierarchy Problem with a Light Singlet and Supersymmetric Mass Terms

    Get PDF
    A generalization of the Next-to-Minimal Supersymmetric Model (NMSSM) is studied in which an explicit \mu-term as well as a small supersymmetric mass term for the singlet superfield are incorporated. We study the possibility of raising the Standard Model-like Higgs mass at tree level through its mixing with a light, mostly-singlet, CP-even scalar. We are able to generate Higgs boson masses up to 145 GeV with top squarks below 1.1 TeV and without the need to fine tune parameters in the scalar potential. This model yields light singlet-like scalars and pseudoscalars passing all collider constraints.Comment: 14 pages, 4 figure

    Quantum fluctuations as deviation from classical dynamics of ensemble of trajectories parameterized by unbiased hidden random variable

    Full text link
    A quantization method based on replacement of c-number by c-number parameterized by an unbiased hidden random variable is developed. In contrast to canonical quantization, the replacement has straightforward physical interpretation as statistical modification of classical dynamics of ensemble of trajectories, and implies a unique operator ordering. We then apply the method to develop quantum measurement without wave function collapse \'a la pilot-wave theory.Comment: 14 pages, accepted in Physica

    About the stability of the dodecatoplet

    Full text link
    A new investigation is done of the possibility of binding the "dodecatoplet", a system of six top quarks and six top antiquarks, using the Yukawa potential mediated by Higgs exchange. A simple variational method gives a upper bound close to that recently estimated in a mean-field calculation. It is supplemented by a lower bound provided by identities among the Hamiltonians describing the system and its subsystems.Comment: 5 pages, two figures merged, refs. added, typos correcte

    Quantization from an exponential distribution of infinitesimal action

    Full text link
    A statistical model of quantization based on an exponential distribution of infinitesimal action is proposed. Trajectory which does not extremize the action along an infinitesimal short segment of path is allowed to occur with a very small probability following an exponential law. Planck constant is argued to give the average deviation from the infinitesimal stationary action.Comment: 15 pages, accepted for publication in Physica

    Génération optique de signaux millimétriques à base de modulateurs de phase optiques sans filtrage optique ou RF et sans polarisation électrique

    No full text
    National audienceUn systÚme de génération optique d'ondes millimétriques accordable à base de modulateurs de phase sans filtre RF ni optique et sans tension de polarisation DC est proposé dans cet article. Un signal de 60 GHz est généré par multiplication par 8 à partir d'un signal de 7.5 GHz avec un ratio de suppression électrique en simulation d'environ 50 dB

    Filterless millimetre-wave optical generation using optical phase modulators without DC bias

    No full text
    International audienceA tunable millimetre-wave generator using optical phase modulators with no DC bias and no filters (neither RF nor optical filters) is proposed in this paper. A 60 GHz RF signal is optically generated by multiplying the frequency of an input RF signal at 7.5 GHz by a factor of 8. The electrical suppression ratio is around 50 dB as shown by simulations

    Rheb-TOR signaling promotes protein synthesis, but not glucose or amino acid import, in Drosophila

    Get PDF
    BACKGROUND: The Ras-related GTPase, Rheb, regulates the growth of animal cells. Genetic and biochemical tests place Rheb upstream of the target of rapamycin (TOR) protein kinase, and downstream of the tuberous sclerosis complex (TSC1/TSC2) and the insulin-signaling pathway. TOR activity is regulated by nutritional cues, suggesting that Rheb might either control, or respond to, nutrient availability. RESULTS: We show that Rheb and TOR do not promote the import of glucose, bulk amino acids, or arginine in Drosophila S2 cells, but that both gene products are important regulators of ribosome biogenesis, protein synthesis, and cell size. S2 cell size, protein synthesis, and glucose import were largely insensitive to manipulations of insulin signaling components, suggesting that cellular energy levels and TOR activity can be maintained through insulin/PI3K-independent mechanisms in S2 cell culture. In vivo in Drosophila larvae, however, we found that insulin signaling can regulate protein synthesis, and thus may affect TOR activity. CONCLUSION: Rheb-TOR signaling controls S2 cell growth by promoting ribosome production and protein synthesis, but apparently not by direct effects on the import of amino acids or glucose. The effect of insulin signaling upon TOR activity varies according to cellular type and context

    Lie Algebras and Growth in Branch Groups

    Full text link
    We compute the structure of the Lie algebras associated to two examples of branch groups, and show that one has finite width while the other, the ``Gupta-Sidki group'', has unbounded width. This answers a question by Sidki. More precisely, the Lie algebra of the Gupta-Sidki group has Gelfand-Kirillov dimension log⁥3/log⁥(1+2)\log3/\log(1+\sqrt2). We then draw a general result relating the growth of a branch group, of its Lie algebra, of its graded group ring, and of a natural homogeneous space we call "parabolic space", namely the quotient of the group by the stabilizer of an infinite ray. The growth of the group is bounded from below by the growth of its graded group ring, which connects to the growth of the Lie algebra by a product-sum formula, and the growth of the parabolic space is bounded from below by the growth of the Lie algebra. Finally we use this information to explicitly describe the normal subgroups of the "Grigorchuk group". All normal subgroups are characteristic, and the number of normal subgroups of index 2n2^n is odd and is asymptotically nlog⁥2(3)n^{\log_2(3)}
    • 

    corecore