490 research outputs found
Effects of CP-violating phases in supersymmetry
Recent studies about the impact of the CP-violating complex parameters in
supersymmetry on the decays of third generation squarks and about T-odd
asymmetries in neutralino and chargino production and decay are reviewed. The
CP-even branching ratios of the third generation squarks show a pronounced
dependence on the phases of A_t, A_b, mu and M_1 in a large region of the
supersymmetric parameter space. This could have important implications for stop
and sbottom searches and the MSSM parameter determination in future collider
experiments. We have estimated the expected accuracy in the determination of
the parameters by global fits of measured masses, decay branching ratios and
production cross sections. We have found that the parameter A_t can be
determined with an error of 2 - 3%, whereas the error on A_b is likely to be of
the order of 50 - 100%. In addition we have studied CP-odd observables, like
asymmetries based on triple product correlations, which are necessary to
unambiguously establish CP violation. We have analysed these asymmetries in
neutralino and chargino production with subsequent three-body decays at the
International Linear Collider with longitudinally polarised beams in the MSSM
with complex parameters M_1 and mu. The asymmetries, which appear already at
tree-level because of spin correlation between production and decay, can be as
large as 20% and will therefore be an important tool for the search for
CP-violating effects in supersymmetry.Comment: 13 pages, LaTeX, 7 eps figures, uses appolb.cls, presented at the
final meeting of the European Network ``Physics at Colliders'', Montpellier,
September 26 - 27, 200
A scheme with two large extra dimensions confronted with neutrino physics
We investigate a particle physics model in a six-dimensional spacetime, where
two extra dimensions form a torus. Particles with Standard Model charges are
confined by interactions with a scalar field to four four-dimensional branes,
two vortices accommodating ordinary type fermions and two antivortices
accommodating mirror fermions. We investigate the phenomenological implications
of this multibrane structure by confronting the model with neutrino physics
data.Comment: LATEX, 24 pages, 9 figures, minor changes in the tex
Characterization and functional expression in Escherichia coli of the sodium/proton/glutamate symport proteins of Bacillus stearothermophilus and Bacillus caldotenax
The genes encoding the Na+/H+/L-glutamate symport proteins of the thermophilic organisms Bacillus stearothermophilus (gltT(Bs)) and Bacillus caldotenax (gltT(Bc)) were cloned by complementation of Escherichia coli JC5412 for growth on glutamate as sole source of carbon, energy and nitrogen. The nucleotide sequences of the gltT(Bs) and gltT(Bc), genes were determined. In both cases the translated sequences corresponded with proteins of 421 amino acid residues (96.7% amino acid identity between GltT(Bs) and GltT(Bc)). Putative promoter, terminator and ribosome-binding-site sequences were found in the flanking regions. These expression signals were functional in E coli. The hydropathy profiles indicate that the proteins are hydrophobic and could form 12 membrane-spanning regions. The Na+/H+ CoUpled L-glutamate symport proteins GltT(Bs) and GltT(Bc) are homologous to the strictly H+ coupled L-glutamate transport protein of E. coli K-12 (overall 57.2% identity). Functional expression of glutamate transport activity was demonstrated by uptake of glutamate in whole cells and membrane vesicles. In accordance with previous observations (de Vrij et al., 1989; Heyne et al., 1991), glutamate uptake was driven by the electrochemical gradients of sodium ions and protons
Regulation of Arginine-Ornithine Exchange and the Arginine Deiminase Pathway in Streptococcus lactis
Regulation of Arginine-Ornithine Exchange and the Arginine Deiminase Pathway in Streptococcus lactis
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