EPJ Web of Conferences (Mar 2014)

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

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

Journal volume & issue
Vol. 66
p. 09015


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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.