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Quasi-free Compton scattering and the polarizabilities of the neutron

  • K. Kossert
  • M. Camen
  • F. Wissmann
  • J. Ahrens
  • J.R.M. Annand
  • H.-J. Arends
  • R. Beck
  • G. Caselotti
  • P. Grabmayr
  • O. Jahn
  • P. Jennewein
  • M.I. Levchuk
  • A.I. L'vov
  • J.C. McGeorge
  • A. Natter
  • V. Olmos de León
  • V.A. Petrun'kin
  • G. Rosner
  • M. Schumacher
  • B. Seitz
  • F. Smend
  • A. Thomas
  • W. Weihofen
  • F. Zapadtka

Abstract:

Differential cross-sections for quasi-free Compton scattering from the proton and neutron bound in the deuteron have been measured using the Glasgow/Mainz photon tagging spectrometer at the Mainz MAMI accelerator together with the Mainz [48]cm ;SPMOslash; × [64]cm NaI(Tl) photon detector and the Göttingen SENECA recoil detector. The data cover photon energies ranging from [200]MeV to [400]MeV at θLABγ = 136.2°. Liquid deuterium and hydrogen targets allowed direct comparison of free and quasi-free scattering from the proton. The neutron detection efficiency of the SENECA detector was measured via the reaction p(γ,π+n). The “free” proton Compton scattering cross-sections extracted from the bound proton data are in reasonable agreement with those for the free proton which gives confidence in the method to extract the differential cross-section for free scattering from quasi-free data. Differential cross-sections on the free neutron have been extracted and the difference of the electromagnetic polarizabilities of the neutron has been determined to be αn - βn = 9.8±3.6(stat)+2.1-1.1(syst)±2.2(model) in units of \(\)[10-4]fm3. In combination with the polarizability sum αn + βn = 15.2±0.5 deduced from photoabsorption data, the neutron electric and magnetic polarizabilities, αn = 12.5±1.8(stat)+1.1-0.6(syst)±1.1(model) and βn = 2.7±1.8(stat)+0.6-1.1(syst)±1.1(model) are obtained. The backward spin polarizability of the neutron was determined to be γ(n)π = (58.6±4.0)×10-4fm4.

PACS. 13.60.Fz Elastic and Compton scattering – 14.20.Dh Protons and neutrons – 25.20.Dc Photon absorption and scattering 

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Copyright information

© Società Italiana di Fisica and Springer-Verlag 2003

Authors and Affiliations

  • K. Kossert
    • 1
  • M. Camen
    • 1
  • F. Wissmann
    • 1
  • J. Ahrens
    • 2
  • J.R.M. Annand
    • 3
  • H.-J. Arends
    • 2
  • R. Beck
    • 2
  • G. Caselotti
    • 2
  • P. Grabmayr
    • 4
  • O. Jahn
    • 2
  • P. Jennewein
    • 2
  • M.I. Levchuk
    • 5
  • A.I. L'vov
    • 6
  • J.C. McGeorge
    • 3
  • A. Natter
    • 4
  • V. Olmos de León
    • 2
  • V.A. Petrun'kin
    • 6
  • G. Rosner
    • 3
  • M. Schumacher
    • 1
  • B. Seitz
    • 1
  • F. Smend
    • 1
  • A. Thomas
    • 2
  • W. Weihofen
    • 1
  • F. Zapadtka
    • 1
  1. 1.II. Physikalisches Institut, Universität Göttingen, D-37073 Göttingen, GermanyDE
  2. 2.Institut für Kernphysik, Universität Mainz, D-55099 Mainz, GermanyDE
  3. 3.Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UKGB
  4. 4.Physikalisches Institut, Universität Tübingen, D-72076 Tübingen, GermanyDE
  5. 5.B.I. Stepanov Institute of Physics, Belarussian Academy of Sciences, 220072 Minsk, BelarusBY
  6. 6.P.N. Lebedev Physical Institute, 117924 Moscow, RussiaRU

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