15 research outputs found
Welche Roboter brauchen wir? Starker Zuwachs der Industrierobotereinsaetze
No full textS.25-29 : Abb.57Nr.
A Measurement of the to Production Ratio in 920 GeV/c Proton-Nucleus Interactions.
No full textRatios of the ψ′ over the J/ψ production cross sections in the dilepton channel for C, Ti and W targets have been measured in 920 GeV proton-nucleus interactions with the HERA-B detector at the HERA storage ring. The ψ′ and J/ψ states were reconstructed in both the μ+μ- and the e+e- decay modes. The measurements covered the kinematic range -0.35≤xF≤0.1 with transverse momentum pT≤4.5 GeV/c. The angular dependence of the ratio has been used to measure the difference of the ψ′ and J/ψ polarization. All results for the muon and electron decay channels are in good agreement: their ratio, averaged over all events, is Rψ′(μ)/Rψ′(e)=1.00±0.08±0.04. This result constitutes a new, direct experimental constraint on the double ratio of branching fractions, (B′(μ)B(e))/(B(μ)B′(e)), of ψ′ and J/ψ in the two channels. The ψ′ to J/ψ production ratio is almost constant in the covered xF range and shows a slow increase with pT
Production of the Charmonium States and in Proton Nucleus Interactions at GeV.
No full textA measurement of the ratio R χ c = ( χ c → J / ψ + γ ) / J / ψ in p C , p Ti , and p W interactions at 920 GeV / c ( √ s = 41.6 GeV ) in the Feynman-x range − 0.35 < x J / ψ F < 0.15 is presented. Both μ + μ − and e + e − J / ψ decay channels are observed with an overall statistics of about 15 000 χ c events, which is by far the largest available sample in pA collisions. The result is R χ c = 0.188 ± 0.013 st + 0.024 − 0.022 sys averaged over the different materials, when no J / ψ and χ c polarizations are considered. The χ c 1 to χ c 2 production ratio R 12 = R χ c 1 / R χ c 2 is measured to be 1.02 ± 0.40 , leading to a cross section ratio σ ( χ c 1 ) σ ( χ c 2 ) = 0.57 ± 0.23 . The dependence of R χ c on the Feynman-x of the J / ψ , x J / ψ F , and its transverse momentum, p J / ψ T , is studied, as well as its dependence on the atomic number, A, of the target. For the first time, an extensive study of possible biases on R χ c and R 12 due to the dependence of acceptance on the polarization states of J / ψ and χ c is performed. By varying the polarization parameter, λ obs , of all produced J / ψ 's by two sigma around the value measured by HERA-B, and considering the maximum variation due to the possible χ c 1 and χ c 2 polarizations, it is shown that R χ c could change by a factor between 1.02 and 1.21 and R 12 by a factor between 0.89 and 1.16
J/ψ production via χc decays in 920 GeV pA interactions
No full textUsing data collected by the HERA-B experiment, we have measured the fraction of J/ψ's produced via radiative χc decays in interactions of 920 GeV protons with carbon and titanium targets. We obtained Rχc= 0.32±0.06stat±0.04sys for the fraction of J/ψ from χc decays averaged over proton–carbon and proton–titanium collisions. This result is in agreement with previous measurements and is compared with theoretical predictions
Measurement of the Upsilon production cross section in 920 GeV fixed-target proton-nucleus collisions
No full textThe cross section ratio RJ/ψ=Br(Υ→l+l−)dσ(Υ)/dy|y=0/σ(J/ψ) has been measured with the HERA-B spectrometer in fixed-target proton–nucleus collisions at 920 GeV proton beam energy corresponding to a proton–nucleon c.m.s. energy of √s=41.6 GeV. The combined results for the decay channels Υ→e+e− and Υ→μ+μ− yield a ratio RJ/ψ=(9.0±2.1)×10−6. The corresponding Υ production cross section per nucleon at mid-rapidity (y=0) has been determined to be Br(Υ→l+l−)dσ(Υ)/dy|y=0=4.5±1.1 pb/nucleon
Dammbau im Salzgebirge. Abschlussbericht Projektphase 2 Zeitraum vom 01.07.1989 - 31.12.1992
No full textThe project report presents and explains data obtained by a specific measuring programme, giving evidence of the sealing efficiency of an engineered barrier comprising abutment, long-term barrier, and hydraulic short-term barrier, the sealing performance having been verified for shorter and longer periods of time (up to approx. 500 years). Specific computer codes have been applied for computing and verifying the long-term efficiency of the complex engineered barrier system (artificial structures and surrounding rock). The technical feasibility and the performance of an engineered barrier for reliable sealing of a radwaste repository is thus demonstrated at a scale of 1:1 at the site of the Asse mineDurch ein geeignetes Messprogramm wird der Nachweis der Dichtigkeit eines aus den Komponenten Widerlager, Langzeitdichtung und hydraulische Kurzzeitdichtung erstellten Dammbauwerkes ueber kurze und lange Zeitraeume (bis ca. 500 Jahre) erbracht. Die Berechenbarkeit der langfristigen Wirksamkeit des komplexen Dichtungssystems (Bauwerk, Gebirge) wird unter Verwendung geeigneter Rechenmodelle geprueft. Die technische Realisierbarkeit und die Wirksamkeit eines Dammbauwerkes im Massstab 1:1 wird in Asse demonstriertSIGLEAvailable from TIB Hannover: RO 2674(1994,18) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany); Commission of the European Communities (CEC), Brussels (Belgium)DEGerman
HERA-B: an experiment to study CP violation in the B system using an internal target at the HERA proton ring
No full textAfter a description of a proposal for using the HERA facility as B factory by means of an internal target the proposal for an experiment is described, where Cp violation is studied in the decay B"0#->#J/#psi#K_S for B's inclusively produced in pp-interactions at 800 GeV/c. Chapter 2 presents details of the internal target and the components of the de. Prototypes of the internal target together with simple trigger and detector systems have been installed in the HERA proton ring since 1992, and have evolved into fairly sophisticated tools; the experience gained from these tests is summarized in chapter 3. Chapter 4 describes the simulation of the detector, its expected performance, and the physics reach of the experiment. Logistics and costs of the proposed experiment are addressed in chapter 5. (orig./HSI)Available from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Measurement of the J/ψ production cross section in 920 GeV/c fixed-target proton–nucleus interactions.
No full textThe mid-rapidity (dσpN/dy at y=0) and total (σpN) production cross sections of Jψ mesons are measured in proton–nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The Jψ mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is . In addition, our result is compared with previous measurements.The mid-rapidity (dσpN/dy at y=0) and total (σpN) production cross sections of Jψ mesons are measured in proton–nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The Jψ mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is . In addition, our result is compared with previous measurements
