| 1. |
- Abazov, V. M., et al.
(författare)
-
The upgraded DO detector
- 2006
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
-
Tidskriftsartikel (refereegranskat)abstract
- The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
|
|
| 2. |
- Adolph, C, et al.
(författare)
-
Measurement of the eta -> 3 pi(0) Dalitz plot distribution with the WASA detector at COSY
- 2009
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 677:1-2, s. 24-29
-
Tidskriftsartikel (refereegranskat)abstract
- In the first production run of the WASA experiment at COSY, the eta decay into three neutral pions was measured in proton-proton interactions at a proton beam kinetic energy of 1.4 GeV. The Dalitz plot of the three pious was Studied using 1.2 x 10(5) fully reconstructed events. and the quadratic slope parameter alpha was determined to be -0.027 +/- 0.008(stat) +/- 0.005(syst). The result is consistent with previous measurements and further corroborates the importance of pion-pion final state interactions. (C) 2009 Elsevier B.V. All rights reserved.
|
|
| 3. |
- Ablikim, M., et al.
(författare)
-
Measurements of (XcJ)-> K+K-K+K- decays
- 2006
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
-
Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
|
|
| 4. |
- Birney, Ewan, et al.
(författare)
-
Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
-
Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
|
|
| 5. |
- Zhu, L Y, et al.
(författare)
-
Cross section measurements of charged pion photoproduction in hydrogen and deuterium from 1.1 to 5.5 GeV
- 2005
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 71:4
-
Tidskriftsartikel (refereegranskat)abstract
- The differential cross sections for the gamma n ->pi(-)p and the gamma p ->pi(+)n processes were measured at Jefferson Lab. The photon energies ranged from 1.1 to 5.5 GeV, corresponding to center-of-mass energies from 1.7 to 3.4 GeV. The pion center-of-mass angles varied from 50(degrees) to 110(degrees). The pi(-) and pi(+) photoproduction data both exhibit a global scaling behavior at high energies and high transverse momenta, consistent with the constituent counting rule prediction and the existing pi(+) data. The data suggest possible substructure of the scaling behavior, which might be oscillations around the scaling value. The data show an enhancement in the scaled cross section at center-of-mass energy near 2.2 GeV. The differential cross section ratios [d sigma/dt(gamma n ->pi(-)p)/d sigma/dt(gamma p ->pi(+)n)] at high energies and high transverse momenta can be described by calculations based on one-hard-gluon-exchange diagrams.
|
|
| 6. |
- Fisher, D., et al.
(författare)
-
The Mt Logan Holocene-late Wisconsinan isotope record : Tropical Pacific-Yukon connections
- 2008
-
Ingår i: Holocene. - : SAGE Publications. ; 18:5, s. 667-677
-
Tidskriftsartikel (refereegranskat)abstract
- The ice core recovered from Prospector Russell Col on Mt Logan (5.4 km a.s.l.), in the Yukon spans over 20 000 years. This unique record offers a Pacific view of the stable isotope and chemical record from the Lateglacial to the present. The timescale is based on seasonal counted years, the largest known volcanic acid signatures and the major shift in stable isotopes and chemistry at the end of the Younger Dryas. There are large and sustained changes in the stable isotopic record that are anti-correlated with marine and continental chemistry series. The oxygen-18 in this area is not a proxy for palaeotemperature but rather for source region. The last major isotope shift in AD 1840 in δ(18O) and chemistry is compared with the Quinn's ENSO record. During periods of more frequent La Niña (stronger tropical easterlies) there is more zonal flow of water vapour transport to the Pacific Northwest, δ(18O) values are larger and the deuterium excess d smaller. These periods coincide with periods of lower accumulation/precipitation in southern Yukon. The Holocene δ(18O) record indicates many large shifts between the meridional (strong El Niño) and zonal (La Niña). Comparison of the Logan isotopic record and the moisture/temperature-sensitive time series of peat bog inception dates for the Northwest shows a strong correlation (0.36) that points to high accumulation rates coincident with low δ(18O) and enhanced meridional flow. Major changes in the core at 4200 BP and 7000—8000 BP point to enhanced meridional flow, which coincide with big changes in the Pacific palaeorecords of the balance between El Niño and La Niña. 4200 BP seems to have inaugurated the `modern' ENSO world.
|
|
| 7. |
|
|
| 8. |
- Kelly, J. J., et al.
(författare)
-
Recoil polarization measurements for neutral pion electroproduction at Q(2)=1(GeV/c)(2) near the Delta resonance
- 2007
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:2
-
Tidskriftsartikel (refereegranskat)abstract
- We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q(2)=1.0 (GeV/c)(2) in 10 bins of 1.17 <= W <= 1.35 GeV across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near the physical mass, W=M-Delta approximate to 1.232 GeV, but the variation among models is large for response functions governed by imaginary parts, and for both types of response functions, the variation increases rapidly with W > M-Delta. We performed a multipole analysis that adjusts suitable subsets of center dot(pi)<= 2 amplitudes with higher partial waves constrained by baseline models. This analysis provides both real and imaginary parts. The fitted multipole amplitudes are nearly model independent-there is very little sensitivity to the choice of baseline model or truncation scheme. By contrast, truncation errors in the traditional Legendre analysis of N ->Delta quadrupole ratios are not negligible. Parabolic fits to the W dependence around M-Delta for the multiple analysis gives values for Re(S1+/M1+)=(-6.61 +/- 0.18)% and Re(E1+/M1+)=(-2.87 +/- 0.19)% for the p pi(0) channel at W=1.232 GeV and Q(2)=1.0 (GeV/c)(2) that are distinctly larger than those from the Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+)=(+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe.
|
|
| 9. |
|
|
| 10. |
|
|
