Search for K~(-pp) Bound State in the d(π~+, K~+) Reaction at J-PARC

摘要

At J-PARC K1.8 beam line, a K~(-pp) bound state is searched in the d(π~+,K~+) reaction at 1.7 GeV/c (J-PARC E27 experiment). The binding energy and decay width of the K~(-pp) bound state can be obtained in the missing mass measurement with a good energy resolution of 2 MeV (FWHM). In order to improve the signal-to-noise ratio, a coincidence measurement of high-momentum protons emitted from non-mesonic K~(-pp) decays with a range counter system is adopted. In June 2012, we have carried out a pilot run. The d(π~+,K~+) missing mass spectrum at 1.7 GeV/c has been obtained for the first time. In this report, an overview of the E27 experiment and a preliminary result on this pilot run are presented.