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We 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 ≈ 0.002 the cross-section for spin-flip is as large as about 2 . 1013 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 . 1010 /(mm2 s) appears to be feasible by means of a radioactive 11C 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 (100MeV) as well as at high (1GeV) energy storage rings providing a time of about one hour for polarisation build-up of about 1010 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. [ABSTRACT FROM AUTHOR]

The table of contents for the present issue of "European Physical Journal A -- Hadrons & Nuclei" is presented.

The recent measurements of the electric form factor of the neutron suggest that its shape may be interpreted as a smooth broad distribution with a bump at Q2 ≈ 0.3 (GeV/c)2 superimposed. As a consequence the corresponding charge distribution in the Breit frame shows a negative charge extending as far out as 2 fm. It is natural to identify this charge with the pion cloud. This realisation is then used to reanalyse all old and new data of the electric and magnetic from factors of the proton and the neutron by a phenomenological fit and by a fit based on the constituent quark model. It is shown that it is possible to fit all form factors coherently with both ansaetzen and that they all show the signal of the pion cloud. [ABSTRACT FROM AUTHOR]

A correction to the article on polarization in antiprotons is presented.

Discusses the publishing policy of the European Physical Journal A. Impact of the world wide web on the publication of scientific work; Disappearance of peer reviewing for publications on electronic servers; Focus of the European Physical Journal A in incorporating essentially all aspects of an electronic server plus the advantages of peer reviewing; Procedures in submitting manuscripts for the European Physical Journal A.

A preface for the November 2007 issue of the "European Physical Journal" is presented.