Search for a light pseudoscalar particle in the decay KL0→π0π0X

Y. C. Tung, Y. B. Hsiung, M. L. Wu, K. F. Chen, J. K. Ahn, Y. Akune, V. Baranov, J. Comfort, M. Doroshenko, Y. Fujioka, T. Inagaki, S. Ishibashi, N. Ishihara, H. Ishii, E. Iwai, T. Iwata, I. Kato, S. Kobayashi, T. K. Komatsubara, A. S. KurilinE. Kuzmin, A. Lednev, H. S. Lee, S. Y. Lee, G. Y. Lim, J. Ma, T. Matsumura, A. Moisseenko, H. Morii, T. Morimoto, T. Nakano, H. Nanjo, J. Nix, T. Nomura, M. Nomachi, R. Ogata, H. Okuno, K. Omata, G. N. Perdue, S. Podolsky, K. Sakashita, T. Sasaki, N. Sasao, H. Sato, T. Sato, M. Sekimoto, T. Shinkawa, Y. Sugaya, A. Sugiyama, T. Sumida, S. Suzuki, Y. Tajima, S. Takita, Z. Tsamalaidze, T. Tsukamoto, Y. Wah, H. Watanabe, M. Yamaga, T. Yamanaka, H. Y. Yoshida, Y. Yoshimura, Y. Zheng

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


We performed a search for a light pseudoscalar particle X in the decay KL0→π0π0X, X→γγ with the E391a detector at KEK. Such a particle with a mass of 214.3MeV/c2 was suggested by the HyperCP experiment. We found no evidence for X and set an upper limit on the product branching ratio for KL0→π0π0X, X→γγ of 2.4×10-7 at the 90% confidence level. Upper limits on the branching ratios in the mass region of X from 194.3 to 219.3MeV/c2 are also presented.

Original languageEnglish
Article number051802
JournalPhysical Review Letters
Issue number5
Publication statusPublished - Feb 2 2009
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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