Investigation of the ReactionMg26(p,t)Mg24nearEp=26MeV

Abstract

Experimental cross sections for the first eight triton groups in the reaction $^{26}\mathrm{Mg}(p,t)^{24}\mathrm{Mg}$ have been measured over an angular range 10-168\ifmmode^\circ\else\textdegree\fi{} (lab) at two incident proton energies, 25.4 and 26.8 MeV. Distorted-wave Born-approximation (DWBA) calculations were able to describe general trends in the angular distributions for low-lying states. However, higher-lying states showed dramatic rearward enhancement relative to the DWBA cross sections. Excitation functions of all eight triton groups have been measured at four angles over a beam energy range 24.96 to 27.20 MeV. The excitation functions are nearly flat for all states; further, the angular distributions show no large changes with energy. These data indicate that compound-nucleus effects are not dominant. Thus the results suggest that the population of the unnatural-parity ${3}^{+}$ state at 5.22-MeV excitation is primarily through a direct-reaction mechanism, possibly a multistep process such as those shown to be important in ($p,t$) reactions by Ascuitto and Glendenning. The roles of spin transfer and multistep effects in the transition to the 5.22-MeV ${3}^{+}$ state in $^{24}\mathrm{Mg}$ were investigated, the latter being the more probable mode of excitation.