Search for a light pseudoscalar particle in the decay K_{L};{0}-->pi;{0}pi;{0}X

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 Kurilin; E 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; E391a Collaboration

doi:10.1103/PhysRevLett.102.051802

Search for a light pseudoscalar particle in the decay K_{L};{0}-->pi;{0}pi;{0}X

Phys Rev Lett. 2009 Feb 6;102(5):051802. doi: 10.1103/PhysRevLett.102.051802. Epub 2009 Feb 5.

Authors

Affiliation

¹ Department of Physics, National Taiwan University, Taipei, Taiwan.

PMID: 19257503
DOI: 10.1103/PhysRevLett.102.051802

Abstract

We performed a search for a light pseudoscalar particle X in the decay K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma with the E391a detector at KEK. Such a particle with a mass of 214.3 MeV/c;{2} was suggested by the HyperCP experiment. We found no evidence for X and set an upper limit on the product branching ratio for K_{L};{0}-->pi;{0}pi;{0}X, X-->gammagamma of 2.4x10;{-7} at the 90% confidence level. Upper limits on the branching ratios in the mass region of X from 194.3 to 219.3 MeV/c;{2} are also presented.