Muon capture by oriented nuclei: new possibilities for studying induced pseudoscalar interaction

Angular distribution of neutrinos (recoil nucleus) in muon capture for an allowed Gamov-Teller transition is considered by taking account of hyperfine effects. This angular distribution is shown to include a correlation of the form P_2(cos A), where A is the angle between the neutrino momentum and the axis specifying the orientation of the initial mesic atom. This correlation, which arises only if the initial mesic atom is aligned, proves highly sensitive to the form factor g_P of induced pseudoscalar interaction. The proposed method for determinating g_P may be realized for the transition 1+ to 2+ from the ground state of the 6-Li nucleus to the narrow resonance of the 6-He nucleus in continuum, as well as in the processes like 10-B(3+) to 10-Be(2+), 11-B(3/2-) to 11-Be(1/2-), 23-Na(3/2+) to 23-Ne(1/2+) with transitions to bound states.