| 1. |
- Eversmann, D., et al.
(författare)
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New Method for a Continuous Determination of the Spin Tune in Storage Rings and Implications for Precision Experiments
- 2015
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:9
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Tidskriftsartikel (refereegranskat)abstract
- A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by nu(s) = gamma G (gamma is the Lorentz factor, G the gyromagnetic anomaly). At 970 MeV/c, the deuteron spins coherently process at a frequency of approximate to 120 kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10(-8), and to 1 x 10(-10) for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
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| 2. |
- Guidoboni, G., et al.
(författare)
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How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97-GeV/c Deuterons in a Storage Ring
- 2016
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 117:5
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Tidskriftsartikel (refereegranskat)abstract
- We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10(-29) e cm.
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| 3. |
- Oellers, D., et al.
(författare)
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Polarizing a stored proton beam by spin flip?
- 2009
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 674:4-5, s. 269-275
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Tidskriftsartikel (refereegranskat)abstract
- We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin-flip cross section in low-energy electron–proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.
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| 4. |
- Augustyniak, W., et al.
(författare)
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Polarization of a stored beam by spin-filtering
- 2012
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 718:1, s. 64-69
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Tidskriftsartikel (refereegranskat)abstract
- The PAX Collaboration has successfully performed a spin-filtering experiment with protons at the COSY-ring. The measurement allowed the determination of the spin-dependent polarizing cross section, that compares well with the theoretical prediction from the nucleon-nucleon potential. The test confirms that spin-filtering can be adopted as a method to polarize a stored beam and that the present interpretation of the mechanism in terms of the proton-proton interaction is correct. The outcome of the experiment is of utmost importance in view of the possible application of the method to polarize a beam of stored antiprotons.
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| 5. |
- Oellers, D., et al.
(författare)
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New experimental upper limit of the electron-proton spin-flip cross-section
- 2014
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 759, s. 6-9
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Tidskriftsartikel (refereegranskat)abstract
- In a previous publication, measurements of the depolarization of a stored proton beam by interaction with a co-propagating unpolarized electron beam at low relative energy have been presented and an upper limit of about 3 x 10(7) b for the electron-proton spin flip cross-section was determined. A refined analysis presented in this paper reduces the previous upper limit by a factor of three by the introduction of a new procedure that, also makes use of non-identified particles.
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| 6. |
- Thörngren Engblom, Pia, et al.
(författare)
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Extensive high-precision studies of proton deuteron breakup reactions at COSY
- 2011
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- We plan to measure the spin dependence of proton deuteron breakup at 30 and 49 MeV proton beam energy where previous measurements are few and limited. The physics objective is to test the predictive power of the chiral effective field theory in the three nucleon continuum by measuring analyzing powers and double spin observables with high precision over large areas of phase space at relevant energies for the theoretical interpretation. The experiment will be done at a newly installed and commissioned low-b section and interaction point in the COSY ring utilizing the PAX Multipurpose Detection System that is presently in the design stage.
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