2,169 research outputs found
Canonical Constraints on Leptonic Cp Violation using UHCR neutrino fluxes
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
Spin-Correlation Coefficients and Phase-Shift Analysis for p+He Elastic Scattering
Angular Distributions for the target spin-dependent observables A,
A, and A have been measured using polarized proton beams at
several energies between 2 and 6 MeV and a spin-exchange optical pumping
polarized He target. These measurements have been included in a global
phase-shift analysis following that of George and Knutson, who reported two
best-fit phase-shift solutions to the previous global p+He elastic
scattering database below 12 MeV. These new measurements, along with
measurements of cross-section and beam-analyzing power made over a similar
energy range by Fisher \textit{et al.}, allowed a single, unique solution to be
obtained. The new measurements and phase-shifts are compared with theoretical
calculations using realistic nucleon-nucleon potential models.Comment: Submitted to Phys. Rev.
Extracting W Boson Couplings from the Production of Four Leptons
We consider the processes , including all possible charged lepton combinations, with
regard to measuring parameters characterizing the boson. We calculate at
what level these processes can be used to measure anamolous triple-boson
vertice coupling parameters for the cases of colliders at 500
and 1 center of mass energies.Comment: 13 pages,OCIP/C-93-
Skew-Zigzag Algebras
We investigate the skew-zigzag algebras introduced by Huerfano and Khovanov. In particular, we relate moduli spaces of such algebras with the cohomology of the corresponding graph
Innovative Feed-In Tariff Designs that Limit Policy Costs
Feed-in tariffs (FITs) are the most prevalent renewable energy policy used globally to date, and there are many benefits to the certainty offered in the marketplace to reduce development risks and associated financing costs and to grow the renewable energy industry. However, concerns over escalating costs in jurisdictions with FIT policies have led to increased attention on cost control in renewable energy policy design. In recent years, policy mechanisms for containing FIT costs have become more refined, allowing policymakers to exert greater control on policy outcomes and on the resulting costs to ratepayers. As policymakers and regulators in the United States begin to explore the use of FITs, careful consideration must be given to the ways in which policy design can be used to balance the policies' advantages while bounding its costs. This report explores mechanisms that policymakers have implemented to limit FIT policy costs. If designed clearly and transparently, such mechanisms can align policymaker and market expectations for project deployment. Three different policy tools are evaluated: (1) caps, (2) payment level adjustment mechanisms, and (3) auction-based designs. The report employs case studies to explore the strengths and weaknesses of these three cost containment tools. These tools are then evaluated with a set of criteria including predictability for policymakers and the marketplace and the potential for unintended consequences
Analytical evidence of enamel hypomineralisation on permanent and primary molars amongst past populations /631/181/19/2471 /692/699 /123 article
Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) involve prevalent qualitative structural developmental anomalies of tooth enamel affecting the first permanent molars (and often incisors) and the second primary molars, respectively. These demarcated hypomineralised lesions of enamel manifest as white-cream or yellow-brown opacities, with possible post-eruptive localised loss of enamel. Aetiological hypotheses have involved contemporary life factors (i.e. environmental pollutant exposure or early childhood medications) in contrast to factors not limited to a specific time period (i.e. hypoxia at birth or genetic predisposition). Evidence of MIH in ancient populations would reinforce aetiological factors present for many centuries. By means of microtomographic and X-ray fluorescence analyses the present study provides evidence that (i) two archaeological specimens: "S407" (Sains-en-Gohelle, France, 12th-16th centuries) and "B335" (Beauvais, France, 15th-18th centuries) were MIH-affected, and (ii) one individual "S323" was affected by HSPM and MIH (Sains-en-Gohelle, France, 7th-11th centuries)
Unraveling the Nature of Charge Excitations in LaCuO with Momentum-Resolved Cu -edge Resonant Inelastic X-ray Scattering
Results of model calculations using exact diagonalization reveal the orbital
character of states associated with different Raman loss peaks in Cu -edge
resonant inelastic X-ray scattering (RIXS) from LaCuO. The model
includes electronic orbitals necessary to highlight non-local Zhang-Rice
singlet, charge transfer and - excitations, as well as states with apical
oxygen 2 character. The dispersion of these excitations is discussed with
prospects for resonant final state wave-function mapping. A good agreement with
experiments emphasizes the substantial multi-orbital character of RIXS profiles
in the energy transfer range 1-6 eV.Comment: Original: 4.5 pages. Replaced: 4 pages and 4 figures with updated
content and reference
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