Angular correlation between annihilation products and K /SUB a/ X ray in -pp annihilation at rest

This chapter demonstrates that the angular correlation of the annihilation products (annihilation from S state) depends on the dynamics of the channel. The annihilation occurs from the fundamental state which is either a 1S /SUB o/ or a 3S1 state if a Kα ray of the quasi atomic protonium system is detected. If the P states decay only through K X ray (no direct annihilation from P state), the annihilation is isotropic with respect to the K X ray direction. If the direct annihilation from the P state is not negligible in comparison with X ray emission, then it can be expected that the annihilation width depends strongly on the total angular momentum