2,167 research outputs found

    Canonical Constraints on Leptonic Cp Violation using UHCR neutrino fluxes

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    It is shown that one can in principle constrain the CP-violating parameter delta from measurements of four independant |V_{ij}|^2, or three of them and a ratio, in the leptonic sector. To quantify our approach, using unitarity, we derive simple expressions in terms of four independant |V_{ij}|^2 for cos(delta) and an expression for sin^2(delta) from J^2. Thus, depending on the values of |V_{ij}| and their accuracy, we can set meaningful limits on |delta|. To illustrate numerically, if |V_{u1}|^2 is close to 0.1 with a 10% precision, and if |V_{e3}^2 is larger than 0.005 and for values of |V_{e2}|^2 and |V_{u3}|^2 that stay within +-0.1 of the current experimental data leads to a bound pi/2 < |delta| < pi. Alternatively, a certain combination of parameters with values of |V_{e3}|^2 larger than 0.01 leads to a closed bound of 73 < |delta| < 103. In general, we find that it is better to use |V_{u1}|^2 or |V_{t1}|^2 as the fourth independant |V_{ij}|^2 and that over most of the parameter space, delta is least sensitive to |V_{e3}|^2. With just three independant measurements (solar, atmospheric and reactor) it is impossible to set limits on the CP phase. In this respect, we study the use of ultra high energy cosmic (UHCR) neutrino fluxes as the additional fourth information. We find that within the SM, neutrino fluxes of all three flavours will be very similar but that pushing current neutrino data to their extreme values still allowed, ratios of cosmic neutrino fluxes can differ by up to 20%; such large discrepancies could imply negligibly small CP-violation. We also study a non radiative neutrino decay model and find that the neutrino fluxes can differ by a factor of up to 3 within this model and that an accuracy of 10% on the neutrino fluxes is sufficient to set interestin limits on delta.Comment: 8 pages, 2 figures, 5 table

    Extracting W Boson Couplings from the e+e−e^{+}e^{-} Production of Four Leptons

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    We consider the processes e+e−→ℓ+ℓâ€Č−ΜΜˉâ€Če^{+}e^{-}\rightarrow \ell^{+} \ell^{\prime -}\nu \bar{\nu}^{\prime}, including all possible charged lepton combinations, with regard to measuring parameters characterizing the WW boson. We calculate at what level these processes can be used to measure anamolous triple-boson vertice coupling parameters for the cases of e+e−e^{+}e^{-} colliders at 500 GeVGeV and 1 TeVTeV center of mass energies.Comment: 13 pages,OCIP/C-93-

    Website Barriers to Employment for People with Disabilities

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    This study involves an analysis of the web content of 30 award winning companies regarding diversity and perceived company openness to employing people with disabilities. The results are mixed: some websites appear designed with disabilities in mind while others reveal constraints to website job access which in turn can result in underemployment and talent underutilization of people with disabilities. Based upon these findings, the authors discuss and make recommendations to optimize website designs that welcome people with disabilities

    Applying dissipative dynamical systems to pseudorandom number generation: Equidistribution property and statistical independence of bits at distances up to logarithm of mesh size

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    The behavior of a family of dissipative dynamical systems representing transformations of two-dimensional torus is studied on a discrete lattice and compared with that of conservative hyperbolic automorphisms of the torus. Applying dissipative dynamical systems to generation of pseudorandom numbers is shown to be advantageous and equidistribution of probabilities for the sequences of bits can be achieved. A new algorithm for generating uniform pseudorandom numbers is proposed. The theory of the generator, which includes proofs of periodic properties and of statistical independence of bits at distances up to logarithm of mesh size, is presented. Extensive statistical testing using available test packages demonstrates excellent results, while the speed of the generator is comparable to other modern generators.Comment: 6 pages, 3 figures, 3 table

    The Yang-Baxter equation for PT invariant nineteen vertex models

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    We study the solutions of the Yang-Baxter equation associated to nineteen vertex models invariant by the parity-time symmetry from the perspective of algebraic geometry. We determine the form of the algebraic curves constraining the respective Boltzmann weights and found that they possess a universal structure. This allows us to classify the integrable manifolds in four different families reproducing three known models besides uncovering a novel nineteen vertex model in a unified way. The introduction of the spectral parameter on the weights is made via the parameterization of the fundamental algebraic curve which is a conic. The diagonalization of the transfer matrix of the new vertex model and its thermodynamic limit properties are discussed. We point out a connection between the form of the main curve and the nature of the excitations of the corresponding spin-1 chains.Comment: 43 pages, 6 figures and 5 table

    Direct measurements of neutron capture on radioactive isotopes

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    We simulated the response of a 4p calorimetric g-detector array to decays of radioactive isotopes on the s-process path. The GEANT 3.21 simulation package was used. The main table contains estimates on the maximum sample size and required neutron flux based on the latest available neutron capture cross section at 30 keV. The results are intended to be used to estimate the feasibility of neutron capture measurements with 4p arrays using the time of flight technique

    Generating-function method for tensor products

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    This is the first of two articles devoted to a exposition of the generating-function method for computing fusion rules in affine Lie algebras. The present paper is entirely devoted to the study of the tensor-product (infinite-level) limit of fusions rules. We start by reviewing Sharp's character method. An alternative approach to the construction of tensor-product generating functions is then presented which overcomes most of the technical difficulties associated with the character method. It is based on the reformulation of the problem of calculating tensor products in terms of the solution of a set of linear and homogeneous Diophantine equations whose elementary solutions represent ``elementary couplings''. Grobner bases provide a tool for generating the complete set of relations between elementary couplings and, most importantly, as an algorithm for specifying a complete, compatible set of ``forbidden couplings''.Comment: Harvmac (b mode : 39 p) and Pictex; this is a substantially reduced version of hep-th/9811113 (with new title); to appear in J. Math. Phy

    Measuring Movement and Social Contact with Smartphone Data: A Real-time Application to COVID-19

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    Tracking human activity in real time and at ïŹne spatial scale is particularly valuable during episodes such as the COVID-19 pandemic. In this paper, we discuss the suitability of smartphone data for quantifying movement and social contact. We show that these data cover broad sections of the US population and exhibit movement patterns similar to conventional survey data. We develop and make publicly available a location exposure index that summarizes county-to-county movements and a device exposure index that quantiïŹes social contact within venues. We use these indices to document how pandemic-induced reductions in activity vary across people and places
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