Search for Θ + via the Pion Induced Reaction at J-PARC: J-PARC E19

J-PARC E19 Experiment: Pentaquark Θ+ Search in Hadronic Reaction at J-PARC

“…The statistics in the mass range of 1510-1550 MeV/c 2 were increased by ∼11% with respect to Ref. [11] owing to the improvement of the analysis efficiency of the beam tracking [14]. No structure corresponding to the Θ + was observed.…”

“…It should be noted that the mass resolution of the first data set was updated after the beam momentum resolution ∆p beam /p beam was determined from the experimental data [14]. In a previous letter [11], ∆p beam /p beam was fixed at the design value of the K1. realistic estimation using the π ± p → K + Σ ± reactions and the calibration data resulted in a slightly worse value of 1.4 × 10 −3 (FWHM).…”

“…The details of the spectrometer system and analysis of both the first and second data samples are described in Refs. [10], [11] and [12], respectively. Here results from an updated analysis of the first data set are reported.…”

“…The central value of the pion beam momentum was set to be 1.37-1.38 and 1.46 GeV/c for the two data sets, in order to match the momentum acceptance of the SKS for the scattered kaons to the kinematics of the Θ + production [11,12].…”

Overview of Hadron Physics at J-PARC

“…There were two physics beam times before the earthquark (Oct. 2010), and after the recovery from earthquake (Feb. 2012), and data were taken with two slightly different beam pion momenta, 1.92 GeV/c and 2.01 GeV/c, respectively. The details about the experiment are reported elsewhere [7,8].…”