5 research outputs found
J-PARC E27 Experiment to Search for a K−pp Bound State
We have carried out an experimental search for the simplest kaonic nucleus, , by using the reaction at = 1.69 GeV/. The differential cross section of this reaction with covering a wide missing-mass range from the production threshold to the region has been measured for the first time. The inclusive missing-mass shape of the and production region was understood with a simple quasi-free picture except for an enhancement at 2.13 GeV/ due to a cusp. An obtained peak attributed to production was significantly shifted to the low mass side compared with the simulation by MeV/
J-PARC E19 Experiment: Pentaquark Θ+ Search in Hadronic Reaction at J-PARC
A search for the Θ^+ pentaquark in the reaction was performed at the J-PARC Hadron Facility. Two data samples were collected in 2010 and 2012 at π beam momenta of 1.92 and 2.0 GeV/c, respectively. No peak structure was observed in the missing mass spectra obtained from either data set. The upper limit for the production cross section averaged over the scattering-angle range of 2° to 15° in the laboratory frame was found to be 0.28 µb/sr. The decay width of the Θ^+ can be directly connected to the production cross section through a theoretical calculation using an effective Lagrangian. The estimated upper limits of the width were 0.41 and 2.8 MeV for the spin-parities of 1/2^+ and 1/2^−, respectively