Search for H-dibaryon at J-PARC with a Large Acceptance TPC

Search for H-dibaryon at J-PARC with a Large Acceptance TPC Conference

Sako, H, Ahn, JK, Baek, KY et al. (2014). Search for H-dibaryon at J-PARC with a Large Acceptance TPC . 66 10.1051/epjconf/20146609015

Sako, H; Ahn, JK; Baek, KY; Bassalleck, B; Fujioka, H; Guo, L; Hasegawa, S; Hicks, K; Honda, R; Hwang, SH; Ichikawa, Y; Ieiri, M; Imai, K; Kim, SH; Kiuchi, R; Lee, HS; Nakazawa, K; Naruki, M; Ni, A; Niiyama, M; Ozawa, K; Park, JY; Park, SH; Ryu, SY; Sato, S; Shirotori, K; Sugimura, H; Sumihara, M; Tanida, K; Takahashi, H; Takahashi, T

H-dibaryon has been predicted as a stable 6-quark color-singlet state. It has been searched for by many experiments but has never been discovered. Recent lattice QCD calculations predict H-dibaryon as a weakly bound or a resonant state close to the LL threshold. E224 and E522 experiments at KEK observed peaks in LL invariant mass spectra near the threshold in (K-, K +) reactions, which were statistically not significant. Therefore, we proposed a new experiment E42 at J-PARC. It will measure decay products of ΛΛ and Λπ-p in a (K-, K +) reaction. We design a large acceptance spectrometer based on a Time Projection Chamber (TPC) immersed in a dipole magnetic field. The TPC surrounds a target to cover nearly 4π acceptance, and accepts K- beams up to 106 counts per second. To suppress drift field distortion at high beam rates, we adopt Gas Electron Multipliers (GEMs) for electron amplification and a gating grid. We show an overview of the experiment, the design of the spectrometer, and the R&D status of the TPC prototype. © Owned by the authors, published by EDP Sciences, 2013.