Pentaquark Θ~+ Search Experiment using Pion Beam at J-PARC

摘要

The pentaquark Θ~+ search experiment via the π~(-p) → K~- X reaction was carried out at the J-PARC hadron facility. No significant peak structure was observed in the missing mass spectrum of the 1.92 GeV/c beam momentum run, from which the upper limit for the production cross section of 0.26 μb/sr was derived. In order to accomplish the more stringent restriction we also performed a measurement with 2.0 GeV/c incident beam momentum. 8.7 × 10~(10) beam pions were incident on a liquid hydrogen target. Adequate performance of the spectrometers was established by analyzing the Σ production data. Preliminary analysis status of this new data is reported.