Nuclear states whose energy is close (in nuclear scale) to the threshold of their production usually have large spatial sizes. This occurs due to “long” tails of wave functions expressed in terms of corresponding variables. For example, the ground state of the 8 B nuclei, which are the main source of high-energy solar neutrinos [1], differs from the threshold of the two-particle channel p + 7 Be by only 130 KeV. This fact leads to the necessity of integrating in the transition matrix elements of the reaction p + 7 Be → 8 B + γ over the region up to 300 fm [2].

The mu-molecular resonances dmuBe-7 and pmuBe-8(2+) as four-body systems are considered. We emphasize the possible long-range (on a nuclear scale) character of the strong interaction which drives the nuclear transition dmuBe-7-->pmuBe-8(2+). The probability of such a process is estimated.