Search for the $Θ^{+}$ pentaquark via the $π^-p\to K^-X$ reaction at 1.92 GeV/$c$
K. Shirotori, T. N. Takahashi, S. Adachi, M. Agnello, S. Ajimura, K. Aoki, H. C. Bang, B. Bassalleck, E. Botta, S. Bufalino, N. Chiga, P. Evtoukhovitch, A. Feli… 展开作者
K. Shirotori, T. N. Takahashi, S. Adachi, M. Agnello, S. Ajimura, K. Aoki, H. C. Bang, B. Bassalleck, E. Botta, S. Bufalino, N. Chiga, P. Evtoukhovitch, A. Feliciello, H. Fujioka, F. Hiruma, R. Honda, K. Hosomi, Y. Ichikawa, M. Ieiri, Y. Igarashi, K. Imai, N. Ishibashi, S. Ishimoto, K. Itahashi, R. Iwasaki, C. W. Joo, M. J. Kim, S. J. Kim, R. Kiuchi, T. Koike, Y. Komatsu, V. V. Kulikov, S. Marcello, S. Masumoto, K. Matsuoka, K. Miwa, M. Moritsu, T. Nagae, M. Naruki, M. Niiyama, H. Noumi, K. Ozawa, N. Saito, A. Sakaguchi, H. Sako, V. Samoilov, M. Sato, S. Sato, Y. Sato, S. Sawada, M. Sekimoto, H. Sugimura, S. Suzuki, H. Takahashi, T. Takahashi, H. Tamura, T. Tanaka, K. Tanida, A. O. Tokiyasu, N. Tomida, Z. Tsamalaidze, M. Ukai, K. Yagi, T. O. Yamamoto, S. B. Yang, Y. Yonemoto, C. J. Yoon, K. Yoshida
The $Θ^+$ pentaquark baryon was searched for via the $π^-p\to K^-X$ reaction in a missing-mass resolution of 1.4 MeV/$c^2$(FWHM) at J-PARC. $π^-$ meson beams were incident on the liquid hydrogen target with the beam momentum of 1.92 GeV/$c$. No peak structure corresponding to the $Θ^+$ mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2$^{\circ}$ to 15$^{\circ}$ in the laboratory frame was obtained to be 0.26 $μ$b/sr in the mass region of 1.51$-$1.55 GeV/$c^2$.The upper limit of the $Θ^+$ decay width using the effective Lagrangian approach was obtained to be 0.72 MeV/$c^2$ and 3.1 MeV/$c^2$ for $J^P_Θ=1/2^+$ and $J^P_Θ=1/2^-$, respectively.
Understanding the nature of the heavy pentaquarks and searching for them in pion-induced reactions
利用开粲强子再散射图研究了反应$π^- p \to π^- J/ψp$。由于再散射振幅中存在三角形奇异性（TS），TS峰可以模拟$J/ψp$不变质量分布中的类五夸克共振，这可能会给我们对奇异态性质的理解带来模糊性.由于TS机制具有高度的过程依赖性，在不同过程中寻找重五夸克态可以帮助我们澄清这些不确定性。
Study of the $γd\to K^{+}K^{-}np$ reaction and an alternative explanation for the "$Θ^{+}(1540)$ pentaquark" peak
我们提出了一个计算的$γd \to K^+ K^- n p $反应的目的，看看是否实验峰观察到的$K^+ n$不变质量约1526兆电子伏，从那里的证据存在的$Θ^+$已被要求，可以得到没有这种共振作为一个结果的过程中的特定动力学和削减应用的实验设置。我们发现，事实的组合确实导致一个峰值约1530兆电子伏的不变质量的$K^+ n$，而不需要调用任何新的共振围绕这个能量。这一点，再加上我们用实验的统计数据证明是很大的统计波动，很可能产生那里观察到的较窄的峰。
First exclusive measurements of the K^-pp state - populated in the pp to K^+ Lambda p reaction at 2.85 GeV
我们分析了在T_p = 2.85 $ GeV to search for a K^-pp (= X) nuclear bound state to be formed in the pp to K^+ + X reaction. The deviation spectra of the K^+ missing-mass MM (K^+) and Lambda p invariant-mass M(Lambda-p) with selection of large-angle proton emission revealed a structure with M_X = 2265 +- 2 MeV/c2 and Gamma_X = 118 +- 8$ MeV时，从pp到K^+ λ p的排它过程的DISTO实验数据。
