Neutralinos in E_6 inspired supersymmetric U(1)' models

The neutralino sector in E_6 inspired supersymmetric models with extra neutral gauge bosons and singlet Higgs fields contains additional gaugino and singlino states compared to the MSSM. We discuss the neutralino mixing in rank 5 and rank 6 models and analyze the supersymmetric parameter space where the light neutralinos have mainly singlino or MSSM character. The neutralino character, resonance effects of the new gauge bosons and, assuming mSUGRA-type RGEs, different selectron masses lead to significant differences between the MSSM and the extended models in neutralino production at an e^+e^- linear collider. Beam polarization may improve the signatures to distinguish between the models. In an appendix, we present the mass terms of the gauge bosons, charginos and sfermions which show a significant different mass spectrum than in the MSSM and give all relevant neutralino couplings.Comment: 26 pages, LaTeX, 5 eps figures; version to be published in EPJ

Neutralino Production with Polarized Beams in Extended Supersymmetric Models

We discuss associated neutralino production e^+ e^- --> \tilde{\chi}^0_1 \tilde{\chi}^0_2 with both beams polarized in the MSSM, NMSSM and an E_6 model. It is shown that neutralinos with a large singlino component can be produced at a high luminosity linear collider in a broad parameter range. Polarization effects in the extended models are compared over the whole parameter space where the lightest neutralino is mainly a singlino. We explain the complete different behavior of these models in some parameter regions, which may help to identify the respective supersymmetric model.Comment: 10 pages, LaTeX, 10 eps figures, contribution to the Proceedings of the "2nd Joint ECFA/DESY Study on Physics and Detectors for a Linear Electron-Positron Collider

Trans-spectral orbital angular momentum transfer via four-wave mixing in Rb vapor

We report the transfer of phase structure and, in particular, of orbital angular momentum from near-infrared pump light to blue light generated in a four-wave-mixing process in Rb-85 vapor. The intensity and phase profile of the two pump lasers at 780 and 776 nm, shaped by a spatial light modulator, influences the phase and intensity profile of light at 420 nm, which is generated in a subsequent coherent cascade. In particular, we observe that the phase profile associated with orbital angular momentum is transferred entirely from the pump light to the blue. Pumping with more complicated light profiles results in the excitation of spatial modes in the blue that depend strongly on phase matching, thus demonstrating the parametric nature of the mode transfer. These results have implications on the inscription and storage of phase information in atomic gases

Zero-mode contribution to the light-front Hamiltonian of Yukawa type models

Light-front Hamiltonian for Yukawa type models is determined without the framework of canonical light-front formalism. Special attention is given to the contribution of zero modes.Comment: 14 pages, Latex, revised version with minor changes, Submitted to J.Phys.