APS » PROLA » Phys. Rev. Lett. » Volume 88 » Issue 4

Phys. Rev. Lett. 88, 042503 (2002) [4 pages]

Proton Energy Spectra in the Nonmesonic Weak Decay of Λ12C and Λ28Si Hypernuclei
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O. Hashimoto1, S. Ajimura5, K. Aoki3, H. Bhang2, T. Hasegawa4 *, H. Hotchi4 †, Y. D. Kim2,3 ‡, T. Kishimoto5, K. Maeda1, H. Noumi3, Y. Ohta4, K. Omata3, H. Outa3, H. Park2, Y. Sato1,3, M. Sekimoto3, T. Shibata3, T. Takahashi1, and M. Youn2,3
1Department of Physics, Tohoku University, Sendai 980-8578, Japan
2Department of Physics, Seoul National University, Seoul 151-742, Korea
3High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
4Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
5Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan

Received 28 September 2001; published 14 January 2002

Numbers of protons per Γ hypernuclear weak decay were measured as a function of proton energy above 40 MeV, explicitly identifying production of Γ hypernuclei by the (π+,K+) reaction. The ratios between the neutron-stimulated to proton-stimulated nonmesonic decay widths, Γ(Λn→nn)/Γ(Λp→np) (  =  Γn/Γp) were extracted by fitting the proton energy spectra. The present result claims that the proton yields are suppressed and the Γn/Γp ratios are close to 1 both for Λ12C and Λ28Si in contradiction to theoretical expectations based on meson exchange models.


©2002 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v88/e042503
DOI: 10.1103/PhysRevLett.88.042503
PACS: 21.80.+a, 13.30.Eg, 13.75.Ev, 23.40.-s

* Present address: School of Allied Health Sciences, Kitazato University, Sagamihara 228-8555, Japan.
† Present address: Physics Department, Brookhaven National Laboratory, Upton, NY 11973.
‡ Present address: Department of Physics, Sejong University, Seoul 143-747, Korea.

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