| 1. |
- Abt, I, et al.
(författare)
-
Inclusive V-0 production cross sections from 920 GeV fixed target proton-nucleus collisions
- 2003
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:2, s. 181-190
-
Tidskriftsartikel (refereegranskat)abstract
- Inclusive differential cross sections dsigma(pA)/dx(F) and dsigma(pA)/dp(t)(2) for the production of K-S(0), Lambda, and (&ULambda;) over bar 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 roots = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dsigma(pA)(K-S(0))/dsigma(pA)(Lambda) and dsigma(pA)((&ULambda;) over bar)/dsigma(pA) (Lambda) are measured to be 6.2 +/- 0.5 and 0.66 +/- 0.07, respectively, for x(F) approximate to -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions da,Ald t also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections sigma(pA) on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon sigma(pN) are compared with results obtained at other energies.
|
|
| 2. |
- Abt, I, et al.
(författare)
-
Measurement of the b(b)over-bar production cross section in 920 GeV fixed-target proton-nucleus collisions
- 2003
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 26:3, s. 345-355
-
Tidskriftsartikel (refereegranskat)abstract
- Using the HERA-B detector, the b (b) over bar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b (b) over bar production was tagged via inclusive bottom quark decays into J/psi by exploiting the longitudinal separation of J/psi --> l(+)l(-) decay vertices from the primary proton-nucleus interaction. Both e(+)e(-) and mu(+)mu(-) channels have been reconstructed and the combined analysis yields the cross section sigma(b (b) over bar) = 32(-12)(+14)(stat) (+6)(-7)(sys) nb/nucleon.
|
|
| 3. |
- Ahrens, J, et al.
(författare)
-
First measurement of the helicity-dependent (gamma)over-right-arrow(p)over-right-arrow -> p eta differential cross-section
- 2003
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 17:2, s. 241-244
-
Tidskriftsartikel (refereegranskat)abstract
- The helicity dependence of the (γ) over right arrow(p) over right arrow -+ peta reaction has been measured for the first time at a center-of-mass angle theta(eta)*= 70degrees in the photon energy range from 780 MeV to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam. and a longitudinally polarized frozen-spin target. The helicity 3/2 cross-section is found to be small and the results for helicity 1/2 agree with predictions from the MAID analysis.
|
|
| 4. |
|
|
| 5. |
- Ahrens, J, et al.
(författare)
-
Helicity dependence of the (gamma)over-right-arrow (p)over-right-arrow -> n pi(+) pi(0) reaction in the second resonance region
- 2003
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 551:1-2, s. 49-55
-
Tidskriftsartikel (refereegranskat)abstract
- The helicity dependence of the total cross section for the (γ) over right arrow(p) over right arrownpi(+) pi(0) reaction has been measured for the first time at incident photon energies from 400 to 800 MeV The measurement was performed with the large acceptance detector DAPHNE at the tagged photon beam facility of the MAMI accelerator in Mainz. This channel is found to be excited predominantly when the photon and proton have a parallel spin orientation, due to the intermediate production of the D-13 resonance. (C) 2002 Elsevier Science B.V. All rights reserved.
|
|
| 6. |
- Ahrens, J, et al.
(författare)
-
Helicity dependence of the gamma p -> N pi channels and multipole analysis in the Delta region
- 2004
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 21:2, s. 323-333
-
Tidskriftsartikel (refereegranskat)abstract
- A high-quality double-polarization data set for the helicity dependence of the total and differential cross-sections for both gammap --> Npi channels in the Delta region has been obtained in the framework of the GDH experiment. The experiment, performed at the Mainz microtron MAMI, used a 4pi detection system, a circularly polarized photon beam, and a longitudinally polarized frozen-spin target. These data are included in the database to perform a multipole analysis to determine the properties of the Delta(1232)-resonance. For the resonant Delta(1232) multipoles we find a very good agreement with previous analyses, while the nonresonant ones show significant deviations.
|
|
| 7. |
- Beck, M., et al.
(författare)
-
A pulse-train laser driven XUV source for picosecond pump-probe experiments in the water window
- 2001
-
Ingår i: Optics Communications. - 0030-4018 .- 1873-0310. ; 190:06-jan, s. 317-326
-
Tidskriftsartikel (refereegranskat)abstract
- We describe the development of a table top soft X-ray source based on a laser produced plasma. The plasma is produced by a Nd:YLF pulse-train laser which delivers pulse trains of up to 400 pulses each of about 25 ps duration, Number and energy of the micropulses are fully computer controlled adjustable for an optimum interaction with a rotating solid target. Spectral, spatial and temporal characteristics of the X-ray emission from Mylar and copper targets have been studied. A calibrated back-illuminated CCD camera together with a slit grating spectrograph were utilized for the measurement of the absolute soft X-ray photon fluxes. The temporal measurements were performed using a streak camera while the plasma size was measured with a zone plate. An application of the system in a X-ray absorption experiment is shown, The advantages of the system in view of possible optical pump and soft X-ray probe experiments will be discussed.
|
|
| 8. |
- Beck, Marc, et al.
(författare)
-
Fabrication and characterization of a molecular adhesive layer for micro- and nanofabricated electrochemical electrodes
- 2002
-
Ingår i: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
-
Konferensbidrag (refereegranskat)abstract
- When making nanoelectrodes for applications in liquid cells it is plausible that the less noble metal layer may be negatively affected, i.e. it will be etched away leading to very unstable conditions during operation. Here we describe a dry method to produce such a molecular layer consisting of mercaptopropyltriethoxysilane (MPTS) making it possible to controllable and reproducibly form a covalently bound monolayer of MPTS to the SiO2 surface. From Photoelectron Spectroscopy measurements we could conclude that the layer thickness corresponds to a monolayer. We have electrochemically characterized such electrodes by cyclic voltammetry. Furthermore, we have successfully patterned such layers at both micro- and nanometer scale showing the possibilities to fabricate chemically selective and active areas that may be used in various applications
|
|
| 9. |
|
|
| 10. |
|
|
