13,786 research outputs found

    Higher Order Stability of a Radiatively Induced 220 GeV Higgs Mass

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    The effective potential for radiatively broken electroweak symmetry in the single Higgs doublet Standard Model is explored to four sequentially subleading logarithm-summation levels (5-loops) in the dominant Higgs self-interaction couplant λ\lambda. We augment these results with all contributing leading logarithms in the remaining large but sub-dominant Standard Model couplants (t-quark, QCD and SU(2)U(1)SU(2)\otimes U(1) gauge couplants) as well as next to leading logarithm contributions from the largest of these, the t-quark and QCD couplants. Order-by-order stability is demonstrated for earlier leading logarithm predictions of an order 220 GeV Higgs boson mass in conjunction with fivefold enhancement of the value for λ\lambda over that anticipated from conventional spontaneous symmetry breaking.Comment: revtex, 6 pages. Analysis and text is expanded in revised versio

    Improvement of Renormalization-Scale Uncertainties Within Empirical Determinations of the b-Quark Mass

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    Accurate determinations of the MS-bar b-quark mass mb(mb)m_b(m_b) from σ(e+ehadrons)\sigma(e^+e^-\to{\rm hadrons}) experimental data currently contain three comparable sources of uncertainty; the experimental uncertainty from moments of this cross-section, the uncertainty associated with αs(Mz)\alpha_s(M_z), and the theoretical uncertainty associated with the renormalization scale. Through resummation of all logarithmic terms explicitly determined in the perturbative series by the renormalization-group (RG) equation, it is shown that the renormalization-scale dependence is virtually eliminated as a source of theoretical uncertainty in mb(mb)m_b(m_b). This resummation also reduces the estimated effect of higher-loop perturbative contributions, further reducing the theoretical uncertainties in mb(mb)m_b(m_b). Furthermore, such resummation techniques improve the agreement between the values of the MS-bar b-quark mass extracted from the various moments of R(s)=σ(e+ehadrons)/σptR(s)=\sigma(e^+e^-\to{\rm hadrons})/\sigma_{pt} [σpt=4πα2/(3s)\sigma_{pt}=4\pi\alpha^2/(3s)], obviating the need to choose an optimummoment for determining mb(mb)m_b(m_b). Resummation techniques are also shown to reduce renormalization-scale dependence in the relation between b-quark MS-bar and pole mass and in the relation between the pole and 1S1S mass.Comment: 19 pages, latex2e, 6 eps figures contained in latex file. Errors corrected in equations (20)--(22

    Real options in the context of innovation and development policies and practices. ACES Working Papers, 2012

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    This paper proposes to build on previous research on the use of real options in strategic decision making (Carayannis and Sipp, 2010) and instill some real options-related concepts stemming from systems design, more particularly engineering. It also builds on previously-established concepts of strategic knowledge serendipity and arbitrage and strategic knowledge co-opetition, co-evolution and co-specialization developed by Carayannis (2009). The application of real options “in” system and real options to innovation and innovation policies demonstrate how embedded real options can more effectively be identified and therefore the decision to execute them or not more effectively made

    Pade-Improved Estimate of Perturbative Contributions to Inclusive Semileptonic bub\to u Decays

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    Pade-approximant methods are used to estimate the three-loop perturbative contributions to the inclusive semileptonic bub \to u decay rate. These improved estimates of the decay rate reduce the theoretical uncertainty in the extraction of the CKM matrix element Vub|V_{ub}| from the measured inclusive semileptonic branching ratio.Comment: 3 pages, latex, write-up of talk presented at DPF 200

    Lumped mass modelling for the dynamic analysis of aircraft structures

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    Aircraft structures may be modelled by lumping the masses at particular strategic points and the flexibility or stiffness of the structure is obtained with reference to these points. Equivalent moments of inertia for the section at these positions are determined. The lumped masses are calculated based on the assumption that each point will represent the mass spread on one half of the space on each side. Then these parameters are used in the differential equation of motion and the eigen characteristics are determined. A comparison is made with results obtained by other established methods. The lumped mass approach in the dynamic analysis of complicated structures provides an easier means of predicting the dynamic characteristics of these structures. It involves less computer time and avoids computational errors that are inherent in the numerical solution of complicated systems

    Radiative Electroweak Symmetry-Breaking Revisited

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    In the absence of a tree-level scalar-field mass, renormalization-group methods permit the explicit summation of leading-logarithm contributions to all orders of the perturbative series within the effective potential for SU(2)×U(1)SU(2)\times U(1) electroweak symmetry. This improvement of the effective potential function is seen to reduce residual dependence on the renormalization mass scale. The all-orders summation of leading logarithm terms involving the dominant three couplings contributing to radiative corrections is suggestive of a potential characterized by a plausible Higgs boson mass of 216 GeV. However, the tree potential's local minimum at ϕ=0\phi =0 is restored if QCD is sufficiently strong.Comment: revtex, 4 pages, 1 eps figure embedded in manuscript. Updated version contains additional comments and corrects minor error
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