We have measured the proton energy distribution from the 4He(stopped K−,p) reaction by means of time-of-flight. A mono-energetic peak was observed, which is interpreted as the formation of a new kind of neutral tribaryon S0(3115) with isospin T=1 and strangeness S=−1. The mass and width of the state were deduced to be 3117.0−4.4+1.5MeV/c2 and <21MeV/c2, respectively. The state mainly decays into ΣNN

Thermal muonium (positive muon ${\mu }^{+}$ and electron $e^{-}$) atoms were produced from the surface of a hot (2300 K) and high purity tungsten foil placed at the primary beam of 500 MeV pulsed protons. Resonant ionization $\left(1s\to 2p\to \mathrm{unbound}\right)$ of the thermal muonium with pulsed laser sources was achieved with reference to thermal hydrogen isotopes (D and T) so as to produce a potentially intense ultraslow (as low as 0.2 eV) positive muon beam with an extremely narrow phase-space volume and high stopping density.