1. |
- Alcorn, J, et al.
(author)
-
Basic instrumentation for Hall A at Jefferson Lab
- 2004
-
In: 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
-
Journal article (peer-reviewed)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.
|
|
2. |
- Wijesooriya, K, et al.
(author)
-
Polarization measurements in high-energy deuteron photodisintegration
- 2001
-
In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 86:14, s. 2975-2979
-
Journal article (peer-reviewed)abstract
- We present measurements of the recoil proton polarization for the d(γ⃗,p⃗)n reaction at θc.m. = 90° for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization py vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(γ,p)ncross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.
|
|
3. |
- Dutta, D, et al.
(author)
-
Nuclear transparency with the gamma n ->pi(-)p process in He-4
- 2003
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 68:2: 021001
-
Journal article (peer-reviewed)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.
|
|
4. |
- Schulte, EC, et al.
(author)
-
High energy angular distribution measurements of the exclusive deuteron photodisintegration reaction
- 2002
-
In: Physical Review C (Nuclear Physics). - : American Physical Society. - 0556-2813 .- 1089-490X. ; 66:4
-
Journal article (peer-reviewed)abstract
- The first complete measurements of the angular distributions of the two-body deuteron photodisintegration differential cross section at photon energies above 1.6 GeV were performed at the Thomas Jefferson National Accelerator Facility. The results show a persistent forward-backward asymmetry up to E-gamma=2.4 GeV, the highest-energy measured in this experiment. The Hard Rescattering and the Quark-Gluon string models are in fair agreement with the results.
|
|
5. |
- Wijesooriya, K, et al.
(author)
-
Polarization measurements in neutral pion photoproduction
- 2002
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:3
-
Journal article (peer-reviewed)abstract
- We present measurements of the recoil proton polarization for the H-1((γ) over right arrow,(p) over right arrow)pi(0) reaction for theta(c.m.)(pi) = 60degrees-135degrees and for photon energies up to 4.1 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. Various theoretical models are compared with the results. No evidence for hadron helicity conservation is observed. Models that employ factorization are not favored. It appears from the strong angular dependence of the induced polarization at photon energies of 2.5 and 3.1 GeV that a relatively high spin resonance or background amplitude might exist in this energy region.
|
|
6. |
- Zhu, LY, et al.
(author)
-
Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium
- 2003
-
In: Physical Review Letters. - 1079-7114. ; 91:2: 022003
-
Journal article (peer-reviewed)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.
|
|
7. |
- Gayou, O, et al.
(author)
-
Measurement of G(Ep)/G(Mp) in (e)over-right-arrowp -> e(p)over-right-arrow to Q(2)=5.6 GeV2
- 2002
-
In: Physical Review Letters. - 1079-7114. ; 88:9
-
Journal article (peer-reviewed)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.
|
|
8. |
- Andersson, E., et al.
(author)
-
Multimode interferometer for guided matter waves
- 2002
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 88:10
-
Journal article (peer-reviewed)abstract
- Atoms can be trapped and guided with electromagnetic fields, using nanofabricated structures. We describe the fundamental features of an interferometer for guided matter waves, built of two combined Y-shaped beam splitters. We find that such a device is expected to exhibit high contrast fringes even in a multimode regime, analogous to a white light interferometer.
|
|
9. |
- Bartenstein, M, et al.
(author)
-
Atoms and wires: Toward atom chips
- 2000
-
In: IEEE JOURNAL OF QUANTUM ELECTRONICS. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9197. ; 36:12, s. 1364-1377
-
Journal article (peer-reviewed)abstract
- Atoms can be trapped and guided using nanofabricated wires on surfaces, achieving the scales required by quantum information proposals. These atom chips form the basis for robust and widespread application of cold atoms ranging from atom optics to fundame
|
|
10. |
- Brugger, K, et al.
(author)
-
Nanofabricated atom optics: atom chips
- 2000
-
In: JOURNAL OF MODERN OPTICS. - : TAYLOR & FRANCIS LTD. - 0950-0340. ; 47:14-15, s. 2789-2809
-
Journal article (peer-reviewed)abstract
- Small tight trapping and guiding potentials can be created for neutral atoms moving microns above surfaces patterned with nanofabricated charged and current-carrying structures. Surfaces holding such structures form atom chips which, for coherent matter w
|
|
11. |
- Cassettari, D, et al.
(author)
-
Micromanipulation of neutral atoms with nanofabricated structures
- 2000
-
In: APPLIED PHYSICS B-LASERS AND OPTICS. - : SPRINGER VERLAG. - 0946-2171. ; 70:5, s. 721-730
-
Journal article (peer-reviewed)abstract
- A large variety of trapping and guiding potentials can be designed by bringing cold atoms close to charged or current cal lying material objects. We describe the basic principles of constructing microscopic traps and guides and how to load atoms into them
|
|