44 research outputs found
Inclusive Production Cross Sections from 920 GeV Fixed Target Proton-Nucleus Collisions
Inclusive differential cross sections and
for the production of \kzeros, \lambdazero, and
\antilambda particles are measured at HERA in proton-induced reactions on C,
Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to
GeV in the proton-nucleon system. The ratios of differential
cross sections \rklpa and \rllpa are measured to be and , respectively, for \xf . No significant dependence upon the
target material is observed. Within errors, the slopes of the transverse
momentum distributions also show no significant
dependence upon the target material. The dependence of the extrapolated total
cross sections on the atomic mass of the target material is
discussed, and the deduced cross sections per nucleon are
compared with results obtained at other energies.Comment: 17 pages, 7 figures, 5 table
The QCD transition temperature: results with physical masses in the continuum limit II.
We extend our previous study [Phys. Lett. B643 (2006) 46] of the cross-over
temperatures (T_c) of QCD. We improve our zero temperature analysis by using
physical quark masses and finer lattices. In addition to the kaon decay
constant used for scale setting we determine four quantities (masses of the
\Omega baryon, K^*(892) and \phi(1020) mesons and the pion decay constant)
which are found to agree with experiment. This implies that --independently of
which of these quantities is used to set the overall scale-- the same results
are obtained within a few percent. At finite temperature we use finer lattices
down to a <= 0.1 fm (N_t=12 and N_t=16 at one point). Our new results confirm
completely our previous findings. We compare the results with those of the
'hotQCD' collaboration.Comment: 19 pages, 8 figures, 3 table
Characterization of silicon microstrip detectors using an infrared laser system
An infrared laser system with variable wavelength is used to study fundamental properties of silicon microstrip detectors. Results of measurements concerning charge sharing among adjacent readout strips and depletion mapping are presented. The results are interpreted in a model framework which describes the charge sharing with the help of the so-called η-function. The wavelength dependence of the η-function is studied. Surface effects important for short wavelengths are observed
Double sided microstrip detectors for the high radiation environment in the HERA-B experiment
The design of the double sided microstrip detectors for the HERA-B experiment at DESY is discussed, in particular with respect to the strong requirements imposed by the high radiation environment and by the challenging mechanical construction. The detectors are tested with an infrared laser setup and first results from operation in the experiment in 1997 are presented. (orig.)15 refs.Available from TIB Hannover: RA 2316(99-05) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Molecular basis of functional diversity of voltage-gated potassium channels in mammalian brain
Cloning and sequencing of cDNAs isolated from a rat cortex cDNA library reveals that a gene family encodes several highly homologous K+ channel forming (RCK) proteins. Functional characterization of the channels expressed in Xenopus laevis oocytes following microinjection of in vitro transcribed RCK-specific RNAs shows that each of the RCK proteins forms K+ channels that differ greatly in both their functional and pharmacological properties. This suggests that the molecular basis for the diversity of voltage-gated K+ channels in mammalian brain is based, at least partly, on the expression of several RCK proteins by a family of genes and their assembly to homooligomeric K+ channels with different functional properties
Characterization of silicon microstrip detectors using an infrared laser system
An infrared laser system with variable wavelength is used to study fundamental properties of silicon microstrip detectors. Results of measurements concerning charge sharing among adjacent readout strips and depletion mapping are presented. The results are interpreted in a model framework which describes the charge sharing with the help of the so called #eta#-function. The wavelength dependence of the #eta#-function is studied. Surface effects important for short wavelengths are observed. (orig.)Available from TIB Hannover: RR 2916(98-13) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman