3,753 research outputs found
Measured limits to contamination of optical surfaces by elastomers in vacuum
We have monitored the reflectivity of mirrors that were exposed to a fluoroelastomer (3M-Fluorel 2176) and a room-temperature vulcanizing silicone rubber (RTV-615) in vacuum. The 95% confidence limit on the decrease of mirror reflectivities was less than 0.35 ppm/week for Fluorel and <0.29 ppm@week for RTV-615
3-loop heavy flavor Wilson coefficients in deep-inelastic scattering
We present our most recent results on the calculation of the heavy flavor
contributions to deep-inelastic scattering at 3-loop order in the large
limit, where the heavy flavor Wilson coefficients are known to factorize into
light flavor Wilson coefficients and massive operator matrix elements. We
describe the different techniques employed for the calculation and show the
results in the case of the heavy flavor non-singlet and pure singlet
contributions to the structure function .Comment: 4 pages Latex, 2 style files, 4 Figures, Contribution to the
Proceedings of QCD '14, Montpellier, Jult 201
Electromagnetic multipole theory for optical nanomaterials
Optical properties of natural or designed materials are determined by the
electromagnetic multipole moments that light can excite in the constituent
particles. In this work we present an approach to calculate the multipole
excitations in arbitrary arrays of nanoscatterers in a dielectric host medium.
We introduce a simple and illustrative multipole decomposition of the electric
currents excited in the scatterers and link this decomposition to the classical
multipole expansion of the scattered field. In particular, we find that
completely different multipoles can produce identical scattered fields. The
presented multipole theory can be used as a basis for the design and
characterization of optical nanomaterials
3-Loop Corrections to the Heavy Flavor Wilson Coefficients in Deep-Inelastic Scattering
A survey is given on the status of 3-loop heavy flavor corrections to
deep-inelastic structure functions at large enough virtualities .Comment: 13 pages Latex, 8 Figures, Contribution to the Proceedings of EPS
2015 Wie
Recent progress on the calculation of three-loop heavy flavor Wilson coefficients in deep-inelastic scattering
We report on our latest results in the calculation of the three-loop heavy
flavor contributions to the Wilson coefficients in deep-inelastic scattering in
the asymptotic region . We discuss the different methods used to
compute the required operator matrix elements and the corresponding Feynman
integrals. These methods very recently allowed us to obtain a series of new
operator matrix elements and Wilson coefficients like the flavor non-singlet
and pure singlet Wilson coefficients.Comment: 11 pages Latex, 2 Figures, Proc. of Loops and Legs in Quantum Field
Theory, April 2014, Weimar, German
Multipole nonlinearity of metamaterials
We report on the linear and nonlinear optical response of metamaterials
evoked by first and second order multipoles. The analytical ground on which our
approach bases permits for new insights into the functionality of
metamaterials. For the sake of clarity we focus here on a key geometry, namely
the split-ring resonator, although the introduced formalism can be applied to
arbitrary structures. We derive the equations that describe linear and
nonlinear light propagation where special emphasis is put on second harmonic
generation. This contribution basically aims at stretching versatile and
existing concepts to describe light propagation in nonlinear media towards the
realm of metamaterials.Comment: 7 pages, 3 figure
Measurements of Lifetimes and a Limit on the Lifetime Difference in the Neutral D-Meson System
Using the large hadroproduced charm sample collected in experiment E791 at
Fermilab, we report the first directly measured constraint on the decay-width
difference Delta Gamma for the mass eigenstates of the D0-D0bar system. We
obtain our result from lifetime measurements of the decays D0 --> K-pi+ and D0
--> K-K+, under the assumption of CP invariance, which implies that the CP
eigenstates and the mass eigenstates are the same. The lifetime of D0 --> K-K+
(the CP-even final state is \tau_KK = 0.410 +/- 0.011 +/- 0.006 ps, and the
lifetime of D0 --> K-pi+ (an equal mixture of CP-odd and CP-even final states
is tau_Kpi = 0.413 +/- 0.003 +/- 0.004 ps. The decay-width difference is Delta
Gamma = 2(Gamma_KK - Gamma_Kpi) = 0.04 +/- 0.14 +/- 0.05 ps^-1. We relate these
measurements to measurements of mixing in the neutral D-meson system.Comment: 8 pages + 3 figures + 2 table
Atomic matter wave scanner
We report on the experimental realization of an atom optical device, that
allows scanning of an atomic beam. We used a time-modulated evanescent wave
field above a glass surface to diffract a continuous beam of metastable Neon
atoms at grazing incidence. The diffraction angles and efficiencies were
controlled by the frequency and form of modulation, respectively. With an
optimized shape, obtained from a numerical simulation, we were able to transfer
more than 50% of the atoms into the first order beam, which we were able to
move over a range of 8 mrad.Comment: 4 pages, 4 figure
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