3,611 research outputs found
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
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