Magnetic quenching experiments in liquid rare gases

Angular-correlation experiments in liquid He, Ne and Ar with no magnetic field all show a narrow momentum component due to the self-trapping of positronium into localized bubble states. We have applied a static magnetic field to these liquids to determine the effect of magnetic quenching on the narrow component intensity. In He and Ne the increases in the narrow component followed theoretical predictions. However, the magnetic field effect in Ar was surprisingly small. We postulate another quenching mechanism, spin-exchange conversions between p-Ps and o-Ps induced by free electrons from the positron spur, is competing with the magnetic field. A simple model describing the magnetic and spin-exchange quenching demonstrates the need to use time dependent conversion rates