A SEARCH FOR DEEPLY-BOUND KAONIC NUCLEAR STATES BY IN-FLIGHT ~3He(K~-,n) REACTION AT J-PARC

摘要

We report on preliminary results of the J-PARC E15 experiment aiming to search for the simplest kaonic-nuclear bound-state, K~-pp, via in-flight ~3He(K~- ,n) reaction. The first physics data-taking was performed with 5 × 10~9 incident kaons on the ~3He target, and 3 × 10~5 neutrons were collected by a forward neutron counter placed 15 m away from center of the target at 0 degrees. The semi-inclusive neutron spectrum shows clear peak structure composed of the quasi-elastic K~-n → K~-n and the charge exchange K~-p → K-bar~0n reactions as expected.