The Atomic Cascade in p̄p and Implications for p̄p Annihilations at Rest
Many experiments at LEAR will study the p̄p interaction at rest via the formation of an atomic bound system of p̄ and p (protonium). Protonium is formed in a highly excited state when the antiproton has been stopped in a target containing gaseous or liquid hydrogen and after it has been captured by a H2 molecule. The subsequent deexcitation process ends with the annihilation of the p̄p atom from an atomic s-, p- or d-state. The knowledge of the angular momentum of this atomic state is clearly of fundamental importance in the analysis of the annihilation final states. The aim of this contribution is to review the present experimental and theoretical understanding of the de-excitation and annihilation process and to show a possible way to calculate the atomic cascade in exotic hydrogen atoms.
KeywordsCascade Process Effective Cross Section Dipole Matrix Element Antiprotonic Helium Wave Contribution
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