Observation of a (6)(LambdaLambda)He double hypernucleus

• Published in: Physical review letters Vol. 87; no. 21; p. 212502
• Main Authors: Takahashi, H, Ahn, J K, Akikawa, H, Aoki, S, Arai, K, Bahk, S Y, Baik, K M, Bassalleck, B, Chung, J H, Chung, M S, Davis, D H, Fukuda, T, Hoshino, K, Ichikawa, A, Ieiri, M, Imai, K, Iwata, Y H, Iwata, Y S, Kanda, H, Kaneko, M, Kawai, T, Kawasaki, M, Kim, C O, Kim, J Y, Kim, S J, Kim, S H, Kondo, Y, Kouketsu, T, Lee, Y L, McNabb, J W, Mitsuhara, M, Nagase, Y, Nagoshi, C, Nakazawa, K, Noumi, H, Ogawa, S, Okabe, H, Oyama, K, Park, H M, Park, I G, Parker, J, Ra, Y S, Rhee, J T, Rusek, A, Shibuya, H, Sim, K S, Saha, P K, Seki, D, Sekimoto, M, Song, J S, Takahashi, T, Takeutchi, F, Tanaka, H, Tanida, K, Tojo, J, Torii, H, Torikai, S, Tovee, D N, Ushida, N, Yamamoto, K, Yasuda, N, Yang, J T, Yoon, C J, Yoon, C S, Yosoi, M, Yoshida, T, Zhu, L
• Format: Journal Article
• Language: English
• Published: United States 19.11.2001
• ISSN: 0031-9007
• DOI: 10.1103/PhysRevLett.87.212502

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.