Antihydrogen production mechanisms in ATHENA

Production of cold antihydrogen in electromagnetic traps by mixing of antiprotons and positrons has been previously reported [M. Amoretti et al., Nature 419 (2002) 456; M. Amoretti et al., Phys. Lett. B 578 (2004) 23; G. Gabrielse et al., Phys. Rev. Lett. 89 (2002) 213401; G. Gabrielse et al., Phys. Rev. Lett. 89 (2002) 233401]. The study of the dependence of the antihydrogen production upon the positron plasma density and temperature is an important tool to distinguish between the possible processes for the formation of antiatoms. In this article results concerning the temperature dependence will be presented, along with a preliminary analysis of the density dependence.