H-dibaryon and hypernucleus formation in the Ξ-12C reaction at rest

J. K. Ahn, S. Aoki, K. S. Chung, M. S. Chung, H. En'yo, T. Fukuda, H. Funahashi, Y. Goto, A. Higashi, M. Ieiri, T. Iijima, M. Iinuma, K. Imai, Y. Itow, J. M. Lee, S. Makino, A. Masaike, Y. Matsuda, Y. Matsuyama, S. MiharaC. Nagoshi, I. Nomura, I. S. Park, N. Saito, M. Sekimoto, Y. M. Shin, K. S. Sim, R. Susukita, R. Takashima, F. Takeutchi, P. Tlustý, S. Weibe, S. Yokkaichi, K. Yoshida, M. Yoshida, T. Yoshida, S. Yamashita

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11 Citations (Scopus)


Stopped-Ξ-12C reactions have been investigated with respect to H-dibaryon and hypernucleus formation with a scintillating fiber detector. Out of 5.5×103 tagged Ξ- particles via the (K-,K+) reaction we obtained 72 stopping Ξ- events with 6.7+1.1-1.4 background events after imposing kinematic constraints. Hypernuclear production has been studied by observing free Λ decays in the stopped-Ξ- reactions. From the observed Λ momentum spectrum, we have found the hypernuclear production rates to be 18±13, 65±6, and 17±12 % for double/twin-A hypernucleus, single-Λ hypernucleus, and no hypernucleus cases, respectively. With the same sample, we set upper limits on R (stopped-Ξ-12C→HX /stopped-Ξ-12C→ all) for H decaying into Λn, Σ-p, and Λpπ-, for H masses just below ΛΛ mass threshold and for H lifetime range 10-11≤τH≤10-8 s. The upper limits on R are ∼0.1-0.2, assuming all of the H decay into each decay mode. Our results give a tight constraint on the existence of the bound H, in comparison with the theoretical estimates of Aerts and Dover, albeit with different target nuclei.

Original languageEnglish
Article number055201
Pages (from-to)552011-5520112
Number of pages4968102
JournalPhysical Review C - Nuclear Physics
Issue number5
Publication statusPublished - 2000 Nov
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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