| 1. |
- Abt, I, et al.
(författare)
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Inclusive V-0 production cross sections from 920 GeV fixed target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:2, s. 181-190
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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.
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| 2. |
- Abt, I, et al.
(författare)
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Measurement of the b(b)over-bar production cross section in 920 GeV fixed-target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 26:3, s. 345-355
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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.
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| 3. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Zhu, Bin, et al.
(författare)
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Innovative solid carbonate-ceria composite electrolyte fuel cells
- 2001
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Ingår i: Electrochemistry communications. - 1388-2481 .- 1873-1902. ; 3:10, s. 566-571
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Tidskriftsartikel (refereegranskat)abstract
- An innovative solid carbonate-oxide composite and related fuel cell (FC) technology is reported, It was discovered that solid carbonate-ceria composite (SCC) electrolytes were highly conductive with the material conductivity level varying from 0.001 to 0.2 S cm(-1) between 400 and 600 degreesC, and related FCs reached a power density between 200 and 600 mW cm(2) at a Current density of 300-1200 mA cm(-2) in the same temperature region. The SCCs were discovered to possess both oxide-ion (originating from the ceria phase) and proton (from the carbonate phase) conduction. Being an all-solid ceramic FC. the SCC can effectively reduce the material corrosion problem that is serious for the molten carbonate fuel cells (MCFCs). On the other hand, the innovative FC technology based on the SCC electrolytes developed in this work is similar to solid oxide fuel cells (SOF'Cs) and different from the MCFCs based on their ionic transport and FC processes, which facilitates a development of new type of advanced FC technology.
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| 6. |
- Fu, Q. X., et al.
(författare)
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Intermediate temperature fuel cells based on doped ceria-LiCl-SrCl2 composite electrolyte
- 2002
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Ingår i: Journal of Power Sources. - 0378-7753 .- 1873-2755. ; 104:1, s. 73-78
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Tidskriftsartikel (refereegranskat)abstract
- A new type of oxide-salt composite electrolyte, gadolinium-doped ceria (GDC)-LiCl-SrCl2, was developed and demonstrated its promising use for intermediate temperature (400-700 degreesC) fuel cells (ITFCs). The dc electrical conductivity of this composite electrolyte (0.09-0.13 S cm(-1) at 500-650 degreesC) was 3-10 times higher than that of the pure GDC electrolyte, indicating remarkable proton or oxygen ion conduction existing in the LiCl-SrCl2 chloride salts or at the interface between GDC and the chloride salts. Using this composite electrolyte, peak power densities of 260 and 510 mW cm(-2), with current densities of 650 and 1250 mA cm(-2) were achieved at 550 and 625 degreesC, respectively. This makes the new material a good candidate electrolyte for future low-cost ITFCs.
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| 7. |
- Ma, W. C., et al.
(författare)
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Competition between terminating and collective structures above spin 40ℏ in 154Dy
- 2002
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 65, s. 1-034312
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in 154Dy were studied with the Gammasphere spectrometer using the 36S(122Sn,4n) reaction. Band terminating states were identified in the spin range I= (36-48)ℏ, and were found to compete with collective rotational cascades up to the highest observed spins. Several "sidebands" feeding the terminating structures were identified as well. A band dominated by M1 transitions was observed to terminate at Iπ = 42-. The data are interpreted within the framework of configuration-dependent cranked Nilsson-Strutinsky calculations without pairing.
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| 8. |
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| 9. |
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| 10. |
- Dutta, D, et al.
(författare)
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Nuclear transparency with the gamma n ->pi(-)p process in He-4
- 2003
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 68:2: 021001
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Tidskriftsartikel (refereegranskat)abstract
- We have measured the nuclear transparency of the fundamental process gamman-->pi(-)p in He-4. These measurements were performed at Jefferson Lab in the photon energy range of 1.6-4.5 GeV and at theta(cm)(pi)=70degrees and 90degrees. These measurements are the first of their kind in the study of nuclear transparency in photoreactions. They also provide a benchmark test of Glauber calculations based on traditional models of nuclear physics. The transparency results suggest deviations from the traditional nuclear physics picture. The momentum transfer dependence of the measured nuclear transparency is consistent with Glauber calculations that include the quantum chromodynamics phenomenon of color transparency.
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