Estimating the deformation of the 12C nucleus from angular correlations in the reactions 11B(α, tγ)12C and 13C(3He, αγ)12C

Data on angular correlations in the reaction B-11(alpha, t gamma)C-12(2(+), 4.44 MeV) at E-alpha = 25 MeV and in the reaction C-13(He-3, alpha gamma)C-12(2(+), 4.44 MeV) at E-3He = 22.5 MeV are compared with theoretical predictions for the processes of nucleon stripping and pickup. In both cases, the parameter of quadrupole deformation of the C-12 nucleus is found to be -0.5. The sign of this parameter is unambiguously inferred from the angular dependence of the spin-tenser components A(4 kappa) of the density matrix for the C-12 nucleus.