| 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. |
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| 4. |
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| 5. |
- Huang, Q., et al.
(författare)
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Code tiling for improving the cache performance of PDE solvers
- 2003
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Ingår i: Proceedings of the International Conference on Parallel Processing. - 0769520170 ; , s. 615-624
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Konferensbidrag (refereegranskat)abstract
- For SOR-like PDE solvers, loop tiling either helps little in improving data locality or hurts their performance. We present a novel compiler technique called code tiling for generating fast tiled codes for these solvers on uniprocessors with a memory hierarchy. Code tiling combines loop tiling with a new array layout transformation called data tiling in such a way that a significant amount of cache misses that would otherwise be present in tiled codes are eliminated. Compared to nine existing loop tiling algorithms, our technique delivers impressive performance speedups (faster by factors of 1.55-2.62) and smooth performance curves across a range of problem sizes on representative machine architectures. The synergy of loop tiling and data tiling allows us to find a problem-size-independent tile size that minimises a cache miss objective function independently of the problem size parameters. This "one-size-fits-all" scheme makes our approach attractive for designing fast SOR solvers without having to generate a multitude of versions specialised for different problem sizes.
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| 6. |
- Xavier, Vera, et al.
(författare)
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Let's study whole-program cache behaviour analytically
- 2002
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Ingår i: Proceedings - International Symposium on High-Performance Computer Architecture. - 0769515258 ; , s. 175-186
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Konferensbidrag (refereegranskat)abstract
- Based on a new characterisation of data reuse across multiple loop nests, we preset a method, a prototyping implementation and some experimental results for analysing the cache behaviour of whole programs with regular computations. Validation against cache simulation using real codes shows the efficiency and accuracy of our method. The largest program, we have analysed, Applu from SPECfP95, has 3868 lines, 16 subroutines and 2565 references. In the case of a 32KB cache with a 32B line size, our method obtains the miss ratio with an absolute error of about 0.80% in about 128 seconds while the simulator used runs for nearly 5 hours on a 933MHz Pentium. III PC. Our method can be used to guide compiler locality optimisations and improve cache simulation performance.
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