Strain-assisted spin manipulating and the discerption of strain-induced spin splitting

We show that the efficiency of manipulating electron spin in semiconductor quantum wells can be enhanced by tuning the strain strength. The effect combining intrinsic and strain-induced spin splitting varies for different systems, which provides an alternative route to understand the experimental phenomena brought in by the strain. The types of spin splittings caused by strain are suggested to be distinguished by the measurement of the electron-dipole-spin-resonance intensity through changing the direction of the $ac$ electric field in the $x$-$y$ plane of the quantum well and tuning the strain strengths.Comment: Revtex, 7 pages, 5 figure

First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters