The cross sections and rates for quenching of thermalized antiprotonic helium atoms in binary collisions with ordinary helium atoms are calculated in perturbation theory and in the coupled-channel formalism at the temperature and the number density of the helium gas, T = 6 K and N = 1021 cm–3, respectively. It is shown that quenching is unlikely to be relevant for the metastable states of the antiprotonic helium atom with 32<=n<=40.> =38.
View online : Phys. Rev. A 69, 042701 (2004)