Detailed L3 measurements of Bose-Einstein correlations and a region of anti-correlations in hadronic Z^0 decays at LEP

L3 preliminary data of two-particle Bose-Einstein correlations are reported for hadronic Z^0 decays in e+e- annihilation at LEP. The invariant relative momentum Q is identified as the eigenvariable of the measured correlation function. Significant anti-correlations are observed in the Bose-Einstein correlation function in a broad region of 0.5 - 1.6 GeV with a minimum at Q close to 0.8 GeV. Absence of Bose-Einstein correlations is demonstrated in the region above Q >= 1.6 GeV. The effective source size is found to decrease with increasing value of the transverse mass of the pair, similarly to hadron-hadron and heavy ion reactions. These feautes and our data are described well by the non-thermal tau-model, which is based on strong space-time momentum-correlations.Comment: 5 pages, 1 figure, invited talk at the XXXIXth International Symposium on Multiparticle Dynamics, Gomel, Belarus, September 200

Dual-frequency ferromagnetic resonance

We describe a new experimental technique to investigate coupling effects between different layers or modes in ferromagnetic resonance (FMR). Dual FMR frequencies are excited (2-8 GHz) simultaneously and detected selectively in a broadband RF circuit, using lock-in amplifier detection at separate modulation frequencies.Comment: 4 pages, 4 figures, accepted by "Review of Scientific Instruments", 200

Measurement of the Scaling Property of Factorial Moments in Hadronic Z Decay

Both three- and one-dimensional studies of local multiplicity fluctuations in hadronic Z decay are performed using data of the L3 experiment at LEP. The normalized factorial moments in three dimensions exhibit power-law scaling, indicating that the fluctuations are isotropic, which correspends to a self-similar fractal. A detailed study of the corresponding one-dimensional moments confirms this conclusion. However, two-jet subsamples have anisotropic fluctuations, correspending to a self-affine fractal. These features are, at least qualitatively, reproduced by the Monte Carlo models \JETSET and \HERWIG.Comment: 4 pages, 4 figures in eps, talk given at XXXI International Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. see http://ismd31.ccnu.edu.cn

New Ideas on SUSY Searches at Future Linear Colliders

Several results obtained within the SUSY group of the ECFA/DESY linear collider study are presented: (i) a possibility to determine tan beta and the trilinear couplings A_f via polarisation in sfermion decays, (ii) the impact of complex MSSM parameters on the third generation sfermion decays, (iii) determination of CP violation in the complex MSSM via T-odd asymmetries in neutralino production and decay, and (iv) an analysis of the chargino and neutralino mass parameters at one-loop level.Comment: 3 pages, LaTeX, 5 eps figures; talk presented by S. Hesselbach at the International Europhysics Conference on High Energy Physics (HEP 2003), 17-23 July 2003, Aachen, German