Advertisement

The European Physical Journal A

, Volume 33, Issue 3, pp 259–263 | Cite as

The quenching of nucleon yields in the nonmesonic weak decay of Λ -hypernuclei and the three-body weak decay process

  • H. BhangEmail author
  • S. Ajimura
  • K. Aoki
  • A. Banu
  • T. Fukuda
  • O. Hashimoto
  • J. I. Hwang
  • S. Kameoka
  • B. H. Kang
  • E. H. Kim
  • J. H. Kim
  • M. Kim
  • T. Maruta
  • Y. Miura
  • Y. Miyake
  • T. Nagae
  • M. Nakamura
  • S. N. Nakamura
  • H. Noumi
  • S. Okada
  • Y. Okayasu
  • H. Outa
  • H. Park
  • P. K. Saha
  • Y. Sato
  • M. Sekimoto
  • S. Shin
  • T. Takahashi
  • H. Tamura
  • K. Tanida
  • A. Toyota
  • K. Tsukada
  • T. Watanabe
  • H. J. Yim
HYP 2006

Abstract.

Recent exclusive coincidence measurements of non-mesonic weak decays (NMWD) reported for the ratio of the partial decay width of neutron-induced-to-proton-induced NMWD, Γnp , values of 0.45±0.11±0.03 and 0.51±0.13±0.04 for 5lam and 12 Λ C , respectively. These observations agree well with the improved theoretical Γnp ratios which are in the range of 0.3-0.7. It appears that the long-standing discrepancy between the experimental and theoretical values of Γnp has finally been solved. However, when compared to the results of intra-nuclear cascade (INC) calculations, the observed numbers of both single nucleons and coincident nucleon pairs are strongly quenched. The quenching of the proton yield observed previously has been interpreted as an increase of the Γnp ratio. On the other hand, significant contributions from the two-nucleon-induced three-body process ΛNNnNN are predicted. Indeed, the angular correlation of the emitted nucleon pairs in the NMWD of 12 Λ C showed not only decay events in back-to-back kinematics, but also events with non-back-to-back kinematics. In this paper we show that the difficulties to extract the correct Γnp ratio from the proton spectra is related to the three-body weak-interaction process which strongly quenches the nucleon yields.

PACS.

21.80.+a Hypernuclei 13.30.Eg Hadronic decays 13.75.Ev Hyperon-nucleon interactions 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    W.M. Alberico, G. Garbarino, Phys. Rep. 369, 1 (2002) and references therein.CrossRefADSGoogle Scholar
  2. 2.
    K. Sasaki, T. Inoue, M. Oka, Nucl. Phys. A 669, 331 (2000)CrossRefADSGoogle Scholar
  3. 3.
    D. Jido, E. Oset, J.E. Palomar, Nucl. Phys. A 694, 525 (2001).CrossRefADSGoogle Scholar
  4. 4.
    K. Itonaga, T. Ueda, T. Motoba, Phys. Rev. C 65, 034617 (2002).CrossRefADSGoogle Scholar
  5. 5.
    Y. Sato, Phys. Rev. C 71, 025203 (2005)CrossRefADSGoogle Scholar
  6. 6.
    J.H. Kim, Phys. Rev. C 68, 065201 (2003).CrossRefADSGoogle Scholar
  7. 7.
    A. Ramos, E. Oset, L.L. Salcedo, Phys. Rev. C 50, 2314 (1994).CrossRefADSGoogle Scholar
  8. 8.
    H. Outa, Nucl. Phys. A 754, 157Google Scholar
  9. 9.
    S. Okada, Phys. Lett. B 597, 249 (2004).CrossRefADSGoogle Scholar
  10. 10.
    M.J. Kim, J. Kor. Phys. Soc. 46, 805 (2005)Google Scholar
  11. 11.
    M.J. Kim, Phys. Lett. B 641, 28 (2006).CrossRefADSGoogle Scholar
  12. 12.
    B.H. Kang, Phys. Rev. Lett. 96, 062301 (2006).CrossRefADSGoogle Scholar
  13. 13.
    G. Garbarino, A. Parreno, A. Ramos, Phys. Rev. Lett. 91, 112501 (2003).CrossRefADSGoogle Scholar

Copyright information

© Società Italiana di Fisica and Springer-Verlag 2007

Authors and Affiliations

  • H. Bhang
    • 1
    Email author
  • S. Ajimura
    • 2
  • K. Aoki
    • 3
  • A. Banu
    • 9
  • T. Fukuda
    • 4
  • O. Hashimoto
    • 5
  • J. I. Hwang
    • 10
  • S. Kameoka
    • 5
  • B. H. Kang
    • 1
  • E. H. Kim
    • 1
  • J. H. Kim
    • 6
  • M. Kim
    • 1
  • T. Maruta
    • 7
  • Y. Miura
    • 5
  • Y. Miyake
    • 2
  • T. Nagae
    • 3
  • M. Nakamura
    • 7
  • S. N. Nakamura
    • 5
  • H. Noumi
    • 3
  • S. Okada
    • 8
  • Y. Okayasu
    • 5
  • H. Outa
    • 3
    • 11
  • H. Park
    • 6
  • P. K. Saha
    • 3
  • Y. Sato
    • 3
  • M. Sekimoto
    • 3
  • S. Shin
    • 10
  • T. Takahashi
    • 3
  • H. Tamura
    • 5
  • K. Tanida
    • 11
  • A. Toyota
    • 3
  • K. Tsukada
    • 5
  • T. Watanabe
    • 5
  • H. J. Yim
    • 1
  1. 1.Department of PhysicsSeoul National UniversitySeoulKorea
  2. 2.Department of PhysicsOsaka UniversityToyonakaJapan
  3. 3.High Energy Accelerator Research Organization (KEK)TsukubaJapan
  4. 4.Laboratory of PhysicsOsaka Electro Communication UniversityNeyagawaJapan
  5. 5.Department of PhysicsTohoku UniversitySendaiJapan
  6. 6.Korea Research Institute of Standards and Science (KRISS)DaejeonKorea
  7. 7.Department of PhysicsUniversity of TokyoHongoJapan
  8. 8.Department of PhysicsTokyo Institute of TechnologyOokayamaJapan
  9. 9.Gesellschaft für Schwerionenforschung mbH (GSI)DarmstadtGermany
  10. 10.Department of PhysicsEwha Womans UniversitySeoulKorea
  11. 11.RIKEN Wako Institute, RIKENWakoJapan

Personalised recommendations