The collision between positronium (Ps) and muonium (Mu)

The collision between a positronium(Ps) and a muonium(Mu) is studied for the first time using the static-exchange model and considering the system as a four-centerCoulomb problem in the centerof mass frame. An exact analysis is made to find the s-wave elastic phase-shifts, the scattering-lengths for both singlet and triplet channels, the integrated/total elastic cross section and the quenching cross section due to orthoto para conversion of Ps and the conversion ratio.