VARIATIONAL CALCULATION OF ANTIPROTONIC HELIUM-ATOMS

A few percent fraction of antiprotons stopped in helium survives for a n enormous time (up to tens of microseconds) in comparison with the us ual lifetime (10(-12) S) of these particles in matter. The explanation is that antiprotons are captured in the metastable antiprotonic heliu m atoms He-3,He-4 (p) over bar e carrying an extremely high total angu lar momentum of L similar to 30-40. Initial populations, level lifetim es, and very precise values of transition energies were obtained in ex periments to measure the resonance laser-induced annihilation. Analogo us long-lived systems were observed in experiments with negative kaons and pions. The purpose of this report is to present the results of ca lculation of the eigenenergies, radiative-transition rates, energy-lev el splitting due to relativistic interactions, and Auger-decay rates o f antiprotonic helium atoms within the variational approach.