The European Physical Journal A

, Volume 32, Issue 4, pp 457–461 | Cite as

The parity violation A4 experiment at forward and backward angles

  • S. BaunackEmail author
PAVI 2006


The A4 Collaboration at the MAMI accelerator in Mainz measures the parity-violating asymmetry in the cross-section of elastic scattering of longitudinally polarized electrons off unpolarized protons from which the contribution of strange sea quarks to the vector form factors of the proton can be derived. Measurements at forward angles 30° ⩽ θ ⩽ 40° and two different momentum transfers Q2 of 0.23 (GeV/c)2 and 0.11 (GeV/c)2 have been performed in the past. Measurements at backward angles 140° ⩽ θ ⩽ 150° are underway for a separate determination of the strange electric and the strange magnetic form factor at Q 2 = 0.23(GeV/c)2 .


13.40.Gp Electromagnetic form factors 11.30.Er Charge conjugation, parity, time reversal, and other discrete symmetries 13.40.-f Electromagnetic processes and properties 14.20.Dh Protons and neutrons 


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  1. 1.
    D.B. Kaplan, Nucl. Phys. B 310, 527 (1988).CrossRefADSGoogle Scholar
  2. 2.
    M.J. Musolf, Phys. Rep. 239, 1 (1994).CrossRefADSGoogle Scholar
  3. 3.
    F. Maas, Phys. Rev. Lett. 93, 022002 (2004).CrossRefADSGoogle Scholar
  4. 4.
    F. Maas, Phys. Rev. Lett. 94, 152001 (2005).CrossRefADSGoogle Scholar
  5. 5.
    J. Friedrich, Eur. Phys. J. A. 17, 706 (2003).CrossRefGoogle Scholar
  6. 6.
    S.-L. Zhu, Phys. Rev. D 69, 033008 (2000).CrossRefADSGoogle Scholar

Copyright information

© Società Italiana di Fisica and Springer-Verlag 2007

Authors and Affiliations

  1. 1.Institut für KernphysikUniversität MainzGermany

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