2,108 research outputs found

    Mean lifetimes of V-particles and heavy mesons

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    A maximum-likelihood procedure for determining mean lifetimes of V-particles from cloud-chamber data is applied to samples taken from a group of 134 neutral V-particle decays. For 74 events which were consistent with a decay into a proton and a negative π-meson, a lifetime of (2.5±0.7)×10-10 sec is obtained. Dividing the data into "low Q" and "high Q" groups on the basis of the calculated energy release in the decay, a value of τL=(2.9±0.8)×10-10 sec is found for those cases with 0<~Q<~50 Mev and a value of τH=(1.6±0.5)×10-10 sec is found for those cases with 50<Q<~150 Mev. While no significant difference exists between these two values, the difference is greater than for other plausible division schemes which are considered. A qualitative discussion of lifetimes is given for the case of 23 charged V-particle decays. For the charged V-particles these data suggest either a lifetime less than that of the neutral V-particles, provided the sample is homogeneous, or, more likely, an apparent average lifetime less than that of the neutral V-particles, if the sample is a mixture of two or more types of particles. The possibility that κ- and/or χ-mesons make up a part of these decays is considered

    Future long-range transports: Prospects for improved fuel efficiency

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    A status report is provided on current thinking concerning potential improvements in fuel efficiency and possible alternate fuels. Topics reviewed are: (1) historical trends in airplane efficiency; (2) technological opportunities including supercritical aerodynamics, (3) vortex diffusers, (4) composite materials, (5) propulsion systems, (6) active controls, and terminal-area operations; (7) unconventional design concepts, and (8) hydrogen-fueled airplane

    Open Space – a collaborative process for facilitating Tourism IT partnerships

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    The success of IT projects depends on the success of the partnerships on which they are based. However past research by the author has identified a significant rate of failure in these partnerships, predominantly due to an overly technical mindset, leading to the question: “how do we ensure that, as technological solutions are implemented within tourism, due consideration is given to human-centred issues?” The tourism partnership literature is explored for additional insights revealing that issues connected with power, participation and normative positions play a major role. The method, Open Space, is investigated for its ability to engage stakeholders in free and open debate. This paper reports on a one-day Open Space event sponsored by two major intermediaries in the UK travel industry who wanted to consult their business partners. Both the running of the event and its results reveal how Open Space has the potential to address some of the weaknesses associated with tourism partnerships

    Anisotropic admixture in color-superconducting quark matter

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    The analysis of color-superconducting two-flavor deconfined quark matter at moderate densities is extended to include a particular spin-1 Cooper pairing of those quarks which do not participate in the standard spin-0 diquark condensate. (i) The relativistic spin-1 gap Delta' implies spontaneous breakdown of rotation invariance manifested in the form of the quasi-fermion dispersion law. (ii) The critical temperature of the anisotropic component is approximately given by the relation T_c'~ Delta'(T=0)/3. (iii) For massless fermions the gas of anisotropic Bogolyubov-Valatin quasiquarks becomes effectively gapless and two-dimensional. Consequently, its specific heat depends quadratically on temperature. (iv) All collective Nambu-Goldstone excitations of the anisotropic phase have a linear dispersion law and the whole system remains a superfluid. (v) The system exhibits an electromagnetic Meissner effect.Comment: v2: references added, angular dependence of the gap clarified, v3: extended discussion, typo in eq. (5) corrected, version accepted for publication in PR

    Spectrum analysis of strong motion earthquakes

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    The problem of the dynamic response of a structure to an earthquake has been formulated in a manner which permits separation of the characteristics of particular structures from the characteristics of the earthquake. The expression involving the characteristics of the earthquake is defined as the "spectrum" of the earthquake and it is shown that the spectrum is simply a plot of the response of a simple oscillator versus the period of the oscillator. Eighty-eight such spectra were computed by means of an electric analog computer and are presented in this report. It is found that damping is a very important parameter in the overall problem; relatively small amounts of damping reduce structural response sharply. It is shown that, when damping is considered, the spectra are consistent with the hypothesis of a distribution about a mean value. It is concluded that the concept of a "dominant ground period" is not valid for the purpose of aseismic structural design. Further research on damping in buildings is recommended, and it is proposed that the mean value of a damped spectrum be used as a quantitative measure of earthquake intensity

    The Ginzburg-Landau Free Energy Functional of Color Superconductivity at Weak Coupling

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    We derive the Ginzburg-Landau free energy functional of color superconductivity in terms of the thermal diagrams of QCD in its perturbative region. The zero mode of the quadratic term coefficient yields the same transition temperature, including the pre-exponential factor, as the one obtained previously from the Fredholm determinant of the two quark scattering amplitude. All coefficients of the free energy can be made identical to those of a BCS model by setting the Fermi velocity of the latter equal to the speed of light. We also calculate the induced symmetric color condensate near TcT_c and find that it scales as the cubic power of the dominant antisymmetric color component. We show that in the presence of an inhomogeneity and a nonzero gauge potential, while the color-flavor locked condensate dominates in the bulk, the unlocked condensate, the octet, emerges as a result of a simultaneous color-flavor rotation in the core region of a vortex filament or at the junction of super and normal phases.Comment: 32 pages, Plain Tex, 3 figure

    Are Textures Natural?

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    We make the simple observation that, because of global symmetry violating higher-dimension operators expected to be induced by Planck-scale physics, textures are generically much too short-lived to be of use for large-scale structure formation.Comment: 9p
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