Bethe-Salpeter type relativistic fermion-antifermion equation in the WKB approximation

We investigate the relativistic fermion-antifermion Bethe-Salpeter type equation whose potential is the sum of Coulomb and linear terms in the WKB approximation. It is shown that in the particular case of an attractive Coulomb potential, the discrete energy spectrum lies in the interval (0,2), and in the case of a repulsive linear potential, in the interval (2, ).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 21–27, September, 1989.