The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{20}$Ne,α ${}^{16}$$O_{g.s.\mathrm{}}^{12}$$C_{g.s}$., ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{20}$Ne,α ${\mathrm{}}^{20}$Ne${)}^8$${\mathrm{Be}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$, and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{20}$Ne,α ${\mathrm{}}^{12}$C${)}^{16}$${\mathrm{O}}^{\mathrm{*}}$ reactions at E${(\mathrm{}}^{20}$Ne)=157 MeV were studied by using position-sensitive telescopes. It was established that α${\mathrm{-}}^{16}$O coincidences in the first reaction result not only from sequential breakup of the projectile, but also from the transfer-reemission process ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$C${(}^{20}$Be${,}^{16}$${\mathrm{O}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$${)}^{16}$${\mathrm{O}}^{\mathrm{*}}$→α+${\mathrm{}}^{12}$ Distributions of the excitation energy in the primary reaction products were deduced by calculating respective branching ratios with a Hauser-Feshbach statistical-decay code. It was found that excitation energy is generated in mass transfer reactions quite asymmetrically: it is mostly concentrated in the nucleus that acquires mass, while the ‘‘donor’’ nucleus, on the average, remains cold. These results clearly support the basic concept of ‘‘spectator’’ models of heavy-ion reactions.

• Received 19 June 1986

DOI:https://doi.org/10.1103/PhysRevC.35.1316