A surprising method for polarising antiprotons

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dc.creatorWalcher, Th.
dc.creatorArenhoevel, H.
dc.creatorAulenbacher, K.
dc.creatorBarday, R.
dc.creatorJankowiak, A.
dc.date2007-06-26
dc.date2007-11-14
dc.date.accessioned2026-07-07T12:43:05Z
dc.date.available2026-07-07T12:43:05Z
dc.descriptionWe propose a method for polarising antiprotons in a storage ring by means of a polarised positron beam moving parallel to the antiprotons. If the relative velocity is adjusted to $v/c \approx 0.002$ the cross section for spin-flip is as large as about $2 \cdot 10^{13}$ barn as shown by new QED-calculations of the triple spin-cross sections. Two possibilities for providing a positron source with sufficient flux density are presented. A polarised positron beam with a polarisation of 0.70 and a flux density of approximately $1.5 \cdot 10^{10}$/(mm$^2$ s) appears to be feasible by means of a radioactive $^{11}$C dc-source. A more involved proposal is the production of polarised positrons by pair production with circularly polarised photons. It yields a polarisation of 0.76 and requires the injection into a small storage ring. Such polariser sources can be used at low (100 MeV) as well as at high (1 GeV) energy storage rings providing a time of about one hour for polarisation build-up of about $10^{10}$ antiprotons to a polarisation of about 0.18. A comparison with other proposals show a gain in the figure-of-merit by a factor of about ten.
dc.description13 pages, 8 figures; v2: minor language and signification corrections v3: (14 pages, 12 figures) major error, nonapplicable polarisation transfer cross sections replaced by the mandatory spin-flip cross sections
dc.identifierhttps://arxiv.org/abs/0706.3765
dc.identifierhttp://arxiv.org/abs/0706.3765
dc.identifierEur.Phys.J.A34:447-461,2007; Erratum-ibid.39:137-138,2009
dc.identifierdoi:10.1140/epja/i2007-10462-x 10.1140/epja/i2008-10705-4
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/220301
dc.subjectAccelerator Physics
dc.titleA surprising method for polarising antiprotons
dc.typetext

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