Pion transfer processes of pionic atoms in the gas mixtures containing hydrogen at various pressures

The pion capture process in gas mixtures containing hydrogen was studied by measuring pionic X rays and π 0 decays. A little difference in pion transfer process was found between the H 2 + D 2 and H 2 O + D 2 O systems. Pressure-dependence of the transfer rates was also revealed in the CH 4 + Ar system by the measurements at several gas pressures. The mechanism of the pion transfer process was discussed based on a comparison between transfer parameters in the gas and liquid phases.