Indication of a strange tribaryon S^+ from the ^4He(stopped K^-,n) reaction
/ Authors
M. Iwasaki, T. Suzuki, H. Bhang, G. Franklin, K. Gomikawa, R. Hayano, T. Hayashi, K. Ishikawa, S. Ishimoto, K. Itahashi
and 19 more authors
T. Katayama, Y. Kondo, Y. Matsuda, T. Nakamura, S. Okada, H. Outa, B.Quinn, M. Sato, M. Shindo, H. So, T. Sugimoto, P. Strasser, K. Suzuki, S. Suzuki, D. Tomono, A. Vinodkumar, E. Widmann, T. Yamazaki, T. Yoneyama
/ Abstract
We measured the neutron time-of-flight spectrum in the ^4He(stopped K^-, n) reaction by stopping negative kaons in a superfluid helium target. A clear enhancement was observed in the neutron spectrum, which indicates the formation of a strange tribaryon of charge +1 with a mass and width of M = 3141 +/- 3 (stat.) +4/-1 (sys.) MeV/c^2 and G < 23 MeV/c^2. This state, denoted as S^+(3140), is about 25 MeV/c^2 higher than the previously observed S^0(3115) T=1.
Journal: arXiv: Nuclear Experiment