Variational calculation of antiprotonic helium atoms

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