Search for $$\Theta ^+$$ in $$K^+d\rightarrow K^0pp$$ reaction at J-PARC

We propose to search for $$\Theta ^+$$ in $$K^+d\rightarrow K^0pp$$ reaction at $$p_{K^+}$$ =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 $$\Theta ^+$$ , such that $$\Theta ^+ \rightarrow K^0 p$$ , followed by $$K^0\rightarrow \pi ^+\pi ^-$$ , with a mass resolution of 1 MeV at $$M_\Theta$$ . We investigated the feasibility of the proposed experiment using a Monte Carlo simulation. As a result, we expect to collect five orders of magnitude $$\Theta ^+$$ events, assuming a cross section of 300 $$\mu$$ b in 15-day beam time at J-PARC.