Simultaneous two-wavelegth tunable dye laser with no mode competition and with a wavelength separation of more than 200 nm

A versatile simultaneous two-wavelength tunable dye laser is described. The two wavelengths are generated by means of a novel pumping arrangement which is suitable for operating with a linewidth between 0.001 nm and the broadband regime. There is no mode competition between the two wavelengths and the power ratio is continuously variable. If required, separate dyes can be used to generate the two wavelengths so facilitating a broad range of wavelength separations. Each wavelength is independently tunable but only one dispersive element is required in the cavity.     

Measurement of single- and double-spin asymmetries in deep inelastic pion electroproduction with a longitudinally polarized target

We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes ? have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q2. A significant nonzero sin2? single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.