Search results for "Mixing"
showing 10 items of 795 documents
Random quasi-phase-matched second-harmonic generation in periodically poled lithium tantalate
2010
We observe second harmonic generation via random quasi-phase-matching in a 2.0 micron periodically poled, 1-cm-long, z-cut lithium tantalate. Away from resonance, the harmonic output profiles exhibit a characteristic pattern stemming from a stochastic domain distribution and a quadratic growth with the fundamental excitation, as well as a broadband spectral response. The results are in good agreement with a simple model and numerical simulations in the undepleted regime, assuming an anisotropic spread of the random nonlinear component. (C) 2010 Optical Society of America
Parametric coherent oscillation with feedback via an orthogonally polarized wave
1999
Coherent light amplification with photorefractive crystals may be a consequence of several frequency degenerate (or nearly degenerate) processes of nonlinear wave mixing : It appears for two- beam coupling in the crystals with diffusion-driven charge transport [1] or transport via circular photovoltaic currents [2].
Transverse patterns in degenerate optical parametric oscillation and degenerate four-wave mixing.
1996
Transverse pattern formation in both degenerate optical parametric oscillation and degenerate four-wave mixing is considered both theoretically and numerically. In the limit of small signal detuning both systems are shown to be described by the real Swift-Hohenberg equation. Contrarily, for small signal and large pump detunings the Swift-Hohenberg equation is modified differently in both systems, by the appearance of additional nonlinear terms, which signal the existence of nonlinear resonances that are theoretically studied through the derivation of the amplitude equation for the roll pattern in both systems. Numerical analysis supports the theoretical predictions. \textcopyright{} 1996 Th…
Peripheral nucleon-nucleon phase shifts and chiral symmetry
1997
Within the one-loop approximation of baryon chiral perturbation theory we calculate all one-pion and two-pion exchange contributions to the nucleon-nucleon interaction. In fact we construct the elastic NN-scattering amplitude up to and including third order in small momenta. The phase shifts with orbital angular momentum $L\geq2 $ and the mixing angles with $J\geq2$ are given parameterfree and thus allow for a detailed test of chiral symmetry in the two-nucleon system. We find that for the D-waves the $2\pi$-exchange corrections are too large as compared with empirical phase shifts, signaling the increasing importance of shorter range effects in lower partial waves. For higher partial waves…
η–η′ mixing in the flavor basis and large N
2010
Abstract The mass matrix for η – η ′ is derived in the flavor basis at O ( p 4 ) of the chiral Lagrangian using the large N approximation. Under certain assumptions, the mixing angle ϕ = 41.4 ° and the decay constants ratio f K / f π = 1.15 are calculated in agreement with the data. It appears that the FKS scheme arises as a special limit of the chiral Lagrangian. Their mass matrix is obtained without the hypothesis on the mixing pattern of the decay constants.
Non-analog β decay of 74Rb
2001
The magnitude of the Coulomb mixing parameter δ 1 has been experimentally deduced, for the first time, for the β decay of 74 Rb. The estimated magnitude is derived from the feeding of the non-analog first excited 0 + state in 74 Kr. The inferred upper limit of 0.07% is small compared to theoretical predictions. The half-life was measured to be 64.90(9) ms. 2001 Published by Elsevier Science B.V.
Atmospheric neutrino oscillations, theta (13) and neutrino mass hierarchy
2003
We derive predictions for the Nadir angle (theta(n)) dependence of the ratio N(mu)/N(e) of the rates of the mu-like and e-like multi-GeV events measured in water-Cerenkov detectors in the case of 3-neutrino oscillations of the atmospheric nu(e) (antinu(e)) and nu(mu) (antinu(mu)), driven by one neutrino mass squared difference, |Delta m2(31)| ~ (2.5 - 3.0) x 10^(-3) eV^2 >> Delta m2(21). This ratio is particularly sensitive to the Earth matter effects in the atmospheric neutrino oscillations, and thus to the values of sin^2(theta(13)) and sin^2(theta(23)), theta(13) and theta(23) being the neutrino mixing angle limited by the CHOOZ and Palo Verde experiments and that responsible for t…
Recommended data on selected gamma-ray and conversion-electron calibration sources
1990
Abstract A compilation of experimental energies and relative intensities for gamma-ray and conversion-electron transitions from the decay of 207Bi, 152Eu, 133Ba, 56Co, and 66Ga is presented. In the cases of known transition multipolarities and mixing ratios calculated values are given for the conversion-electron intensities. Often, these calculated values are more reliable than the measured ones.
Spin correlations at the Z peak. A probe to the Z′ mass
1992
Abstract The interactions of a new heavy gauge boson are fixed by its coupling to matter and by its mass and its mixing with the Z 0 . Until now LEP has only constrained the Z′ mixing. However, there is one observable (and only one), the P - and T -odd transverse-normal spin correlation in ττ production, which fully and independently of its mixing measures the Z′ mass at the Z peak. For M z′ ∼ 130 GeV the Z′ contribution to this observable is typically of the same order as the standard model contribution.
WEAK INTERACTIONS, SYMMETRIES
1981
Abstract The Standard ideas about the breaking of symmetries, through the mechanism of generation mixing, are discussed. New results and proposals looking for discrete space-time symmetry violation as well as flavour-number violation are reported. The use of weak-interaction processes as a tool for both the study of the structure of the currents and for nuclear-structure problems is emphasized.