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Lifetime of heavy hypernuclei and its implications on the weak ΛN interaction

  • W. Cassing
  • L. Jarczyk
  • B. Kamys
  • P. Kulessa
  • H. Ohm
  • K. Pysz
  • Z. Rudy
  • O.W.B. Schult
  • H. Ströher

Abstract:

The lifetime of the Λ-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Jülich has been analyzed to yield τΛ = (145±11) ps. This value for τΛ is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological ΔI = 1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the ΔI = 1/2 rule is discarded in the nonmesonic Λ decay.

PACS. 13.30.-a Decays of baryons – 13.75.Ev Hyperon-nucleon interactions – 21.80.+a Hypernuclei – 25.80.Pw Hyperon-induced reactions 

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Copyright information

© Società Italiana di Fisica and Springer-Verlag 2003

Authors and Affiliations

  • W. Cassing
    • 1
  • L. Jarczyk
    • 2
  • B. Kamys
    • 2
  • P. Kulessa
    • 3
  • H. Ohm
    • 3
  • K. Pysz
    • 3
  • Z. Rudy
    • 2
  • O.W.B. Schult
    • 3
  • H. Ströher
    • 3
  1. 1.Institut für Theoretische Physik, Justus Liebig Universität Giessen, D-35392 Giessen, GermanyDE
  2. 2.M. Smoluchowski Institute of Physics, Jagellonian University, PL-30059 Cracow, PolandPL
  3. 3.Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, GermanyDE

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