Antiproton-He-4 annihilation at rest

摘要

The analysis of about 4 . 10(6) (p) over bar He-4 annihilation events at rest, collected with the OBELIX spectrometer at LEAR, is presented. In some reaction channels with 4 or 5 charged particles in the final state, a preliminary evaluation of the absolute branching ratios for two-nucleon annihilations is made. Moreover, the production of mesonic and baryonic resonances is studied, and for the first time the Pontecorvo reaction (p) over bar He-4 --> 2 pi (-)3p is observed. [References: 5]