| アブストラクト: |
An extremely rare form of subatomic particle decay, the K+ meson turning into a pi+ meson, a neutrino, and an anti-neutirno, has been studied with the high-intensity proton beam available at the Alternating Gradiant Synchrotron of Brookhaven National Laboratory(BNL) in the US. The rare kaon decay is very sensitive to the coupling of top to down quarks, V_{td}, in the Cabibbo-Kobayashi-Maskawa quark mixing matrix, and measurement of the branching ratio provides a stringent test of the standard model of particle physics.
The E949 experiment, which is a successor of the E787 experiment that succeeded in observing the rare decay in 1995-1998, acquired the first physics data in 2002. New results from BNL-E949 based on the analysis of the 2002 dataset are reported in this seminar. |
