Search for Θ ⁺ in K⁺d→ Kpp reaction at J-PARC

We propose to search for Θ ⁺ in K⁺d→ Kpp reaction at pK+=0.5 GeV/c at J-PARC. A large acceptance Hyperon Spectrometer, which consists mainly of a time projection chamber and a 1-T superconducting magnet, will exclusively measure the decay products of Θ ⁺, such that Θ ⁺→ Kp, followed by K→ π⁺π^-, with a mass resolution of 1 MeV at M_Θ. We investigated the feasibility of the proposed experiment using a Monte Carlo simulation. As a result, we expect to collect five orders of magnitude Θ ⁺ events, assuming a cross section of 300 μb in 15-day beam time at J-PARC.