Tung Y C, Hsiung Y B, Wu M L, Chen K F, Ahn J K, Akune Y, Baranov V, Comfort J, Doroshenko M, Fujioka Y, Inagaki T, Ishibashi S, Ishihara N, Ishii H, Iwai E, Iwata T, Kato I, Kobayashi S, Komatsubara T K, Kurilin A S, Kuzmin E, Lednev A, Lee H S, Lee S Y, Lim G Y, Ma J, Matsumura T, Moisseenko A, Morii H, Morimoto T, Nakano T, Nanjo H, Nix J, Nomura T, Nomachi M, Ogata R, Okuno H, Omata K, Perdue G N, Podolsky S, Sakashita K, Sasaki T, Sasao N, Sato H, Sato T, Sekimoto M, Shinkawa T, Sugaya Y, Sugiyama A, Sumida T, Suzuki S, Tajima Y, Takita S, Tsamalaidze Z, Tsukamoto T, Wah Y, Watanabe H, Yamaga M, Yamanaka T, Yoshida H Y, Yoshimura Y, Zheng Y
Department of Physics, National Taiwan University, Taipei, Taiwan.
Phys Rev Lett. 2009 Feb 6;102(5):051802. doi: 10.1103/PhysRevLett.102.051802. Epub 2009 Feb 5.
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.
我们使用日本高能加速器研究机构（KEK）的E391a探测器，在衰变过程(K_{L}^{0}\to\pi^{0}\pi^{0}X)，(X\to\gamma\gamma)中寻找一种轻赝标粒子X。超CP实验曾提出存在一种质量为214.3MeV/c²的此类粒子。我们未找到X存在的证据，并在90%置信水平下对(K_{L}^{0}\to\pi^{0}\pi^{0}X)，(X\to\gamma\gamma)的乘积分支比设定了2.4×10⁻⁷的上限。同时还给出了X质量在194.3至219.3MeV/c²区域内分支比的上限。
