| 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. |
- Nakache, Y P, et al.
(författare)
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Low-complexity ultrawideband transceiver with compatibility to multiband-OFDM
- 2004
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Ingår i: International Workshop on Ultra Wideband Systems, 2004. Joint with Conference on Ultrawideband Systems and Technologies. Joint UWBST & IWUWBS.. - 0780383737 ; , s. 151-155
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Konferensbidrag (refereegranskat)abstract
- We present a low-complexity transceiver for ultrawideband communications with moderate (1-15 Mbit/s) data rate. This transceiver is based on time-frequency-interleaved frequency-shift-keying (TF-FSK), and shows a high degree of compatibility with multiband-OFDM, the currently envisioned standard for high-data-rate (>100 Mbit/s) UWB communications. We show that for dual-mode devices, the major part of the multiband-OFDM transceiver can be reused for the TF-FSK transceiver. We also study the performance of this transceiver in (standardized) UWB channels, and find that, depending on the data rate, coverage ranges of up to 30 m (with LOS connection) are possible.
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| 4. |
- Ramachandran, I, et al.
(författare)
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Symbol spreading for ultrawideband systems based on multiband OFDM
- 2004
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Ingår i: 15th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2004.. - 0780385233 ; 2, s. 1204-1209
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Konferensbidrag (refereegranskat)abstract
- We investigate the effect of symbol spreading on the performance of ultrawideband systems based on multiband OFDM. Ultrawideband channels offer the possibility of very high frequency diversity, as the used bandwidth is much larger than the coherence bandwidth of the channel. In multiband-OFDM, frequency diversity stems from (i) forward error correction coding, which distributes the symbols associated with one bit among different tones, and (ii) interleaving, which distributes the symbols among different employed frequency bands. We show that for weak (rate 3/4) error correcting codes, the achieved diversity order is insufficient. However, the use of Walsh-Hadamard spreading gives additional diversity within each frequency band and greatly improves the performance. Furthermore, we propose a novel scheme for grouping OFDM tones before the spreading is performed. This grouping gives additional flexibility in the system design.
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