116 research outputs found
Further Evidence for the Decay K+ to pi+ neutrino-antineutrino
Additional evidence for the rare kaon decay K+ to pi+ neutrino-antineutrino
has been found in a new data set with comparable sensitivity to the previously
reported result. One new event was observed in the pion momentum region
examined, 211<P<229 MeV/c, bringing the total for the combined data set to two.
Including all data taken, the backgrounds were estimated to contribute 0.15 pm
0.05 events. The branching ratio is B=1.57^{+1.75}_{-0.82} 10^{-10}.Comment: 10 pages, 2 figure
Bandgaps and antiresonances in integrated-ARROWs and Bragg fibers; a simple model
We consider the spectral properties of dielectric waveguides with low refractive index cores and binary layered claddings, such as Bragg fibers and integrated-ARROWs. We show that the full, nontrivial, 2-D spectrum of Bloch bands (hence bandgaps) of such claddings correspond, in structure and topology, to the dispersion properties of both constituent layer types; quantitatively demonstrating an intimate relationship between the bandgap and antiresonance guidance mechanisms. The dispersion functions of these layers, and the interactions thereof, thus form what we coin the Stratified Planar Anti-Resonant Reflecting OpticalWaveguide (SPARROW) model, capable of quantitative, analytic, descriptions of many nontrivial bandgap and antiresonance properties. The SPARROW model is useful for the spectral analysis and design of Bragg fibers and integrated-ARROWs with cores of arbitrary refractive index (equal to or less than the lowest cladding index). Both waveguide types are of interest for sensing and microfluidic applications due to their natural ability to guide light within low-index cores, permitting low-loss guidance within a large range of gases and liquids. A liquid-core Bragg fiber is discussed as an example, demonstrating the applicability of the SPARROW model to realistic and important waveguide designs.Kristopher J. Rowland, Shahraam Afshar V. and Tanya M. Monr
Measurement of the Branching Ratio
Experiment E949 at Brookhaven National Laboratory studied the rare decay
\ and other processes with an exposure of 's. The data were analyzed using a blind analysis technique
yielding one candidate event with an estimated background of
events. Combining this result with the observation of two candidate events by
the predecessor experiment E787 gave the branching ratio
{\calB}(K^+\to\pi^+\nu\bar{\nu})=(1.47^{+1.30}_{-0.89})\times 10^{-10},
consistent with the Standard Model prediction of . This is a more detailed report of results previously published in
Physical Review Letters.Comment: 99 pages, 32 figures, 12 tables. Added authors, corrected typos and
modify the text suggested by the referees. Accepted for publication in PR
Preparation of polymer optical fibers doped with nonlinear optical active organic chromophores
Functional Neurosurgical Simulation with Brain Surface Magnetic Resonance Images and Magnetoencephalography
Photoreduction of carbon dioxide of atmospheric concentration to methane with water over CoAl-layered double hydroxide nanosheets
Broadband transmission in hollow-core Bragg fibers with geometrically distributed multilayered cladding
Hydrogen peroxide-assisted synthesis of oxygen-doped carbon nitride nanorods for enhanced photocatalytic hydrogen evolution
Enabling coherent superpositions of iso-frequency optical states in multimode fibers
The ability to precisely and selectively excite superpositions of specific fiber eigenmodes allows one in principle to control the three dimensional field distribution along the length of a fiber. Here we demonstrate the dynamic synthesis and controlled transmission of vectorial eigenstates in a hollow core cylindrical photonic bandgap fiber, including a coherent superposition of two different angular momentum states. The results are verified using a modal decomposition algorithm that yields the unique complex superposition coefficients of the eigenstate space.United States. Defense Advanced Research Projects AgencyUnited States. Dept. of EnergyUnited States. Army Research Office (Institute for Soldier Nanotechnologies)National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program
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