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| 2. |
- 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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| 3. |
- Badelek, B, et al.
(författare)
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The photon collider at TESLA
- 2004
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Ingår i: International Journal of Modern Physics A. - 0217-751X. ; 19:30, s. 5097-5186
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Forskningsöversikt (refereegranskat)abstract
- High energy photon colliders (gammagamma,gammae) are based on e(-)e(-) linear colliders where high energy photons are produced using Compton scattering of laser light on high energy electrons just before the interaction point. This paper is a part of the Technical Design Report of the linear collider TESLA.(1) Physics program, possible parameters and some technical aspects of the photon collider at TESLA are discussed.
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| 4. |
- Gayou, O, et al.
(författare)
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Measurement of G(Ep)/G(Mp) in (e)over-right-arrowp -> e(p)over-right-arrow to Q(2)=5.6 GeV2
- 2002
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Ingår i: Physical Review Letters. - 1079-7114. ; 88:9
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Tidskriftsartikel (refereegranskat)abstract
- The ratio of the electric and magnetic form factors of the proton G(Ep)/G(Mp), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic (e) over right arrowp --> e (p) over right arrow reaction. The new data presented span the range 3.5 < Q(2) < 5.6 GeV2 and are well described by a linear Q(2) fit. Also, the ratio rootQ(2) F-2p/F-1p reaches a constant value above Q(2) = 2 GeV2.
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| 6. |
- 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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| 7. |
- Yurganov, L.N., et al.
(författare)
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A Quantitative Assessment of the 1998 Carbon Monoxide Emission Anomaly in the Northern Hemisphere Based on Total Column and Surface Concentration Measurements
- 2004
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 109:15, s. D15305-
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Tidskriftsartikel (refereegranskat)abstract
- Carbon monoxide abundances in the atmosphere have been measured between January 1996 and December 2001 in the high Northern Hemisphere (HNH) (30degrees-90degreesN) using two different approaches: total column amounts of CO retrieved from infrared solar spectra and CO mixing ratios measured in situ at ground-based stations. The data were averaged, and anomalies of the CO HNH burden ( deviations of the total tropospheric mass between 30degreesN and 90degreesN from the mean seasonal profile, determined as the 5 year average) were analyzed. The anomalies obtained from in situ and total column data agree well and both show two maxima, by far the largest in October 1998 and a lower one in August 1996. A noticeable decrease of the positive 1998 summer anomaly with increasing height was found. A box model was applied, and anomalies in source rates were obtained under the assumption of insignificant interannual sink variations. In August 1998 the HNH emission anomaly was estimated to be 38 Tg month(-1). The annual 1998 emission positive anomaly was 96 Tg yr(-1). Nearly all excess CO may be attributed to the emissions from boreal forest fires. According to available inventories, biomass burning emits around 52 Tg yr(-1) during the "normal'' years; therefore total biomass emissions in 1998 were as large as 148 Tg yr(-1). In August 1998, CO contribution from the biomass burning was twice as large as that from fossil fuel combustion. The results were compared to available emission inventories.
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| 8. |
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| 9. |
- Zhu, LY, et al.
(författare)
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Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 91:2: 022003
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Tidskriftsartikel (refereegranskat)abstract
- We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma)greater than or similar to3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.
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| 10. |
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