Proton-γangular correlations in the reactionMg24(d,pγ)Mg25

Abstract

The reaction $^{24}\mathrm{Mg}(d,p\ensuremath{\gamma})^{25}\mathrm{Mg}$ has been studied at a deuteron energy of 10 MeV up to an excitation energy in $^{25}\mathrm{Mg}$ of 3.5 MeV. A multidetector arrangement consisting of eight silicon surface-barrier detectors has been used to measure the proton spectra. Particle-$\ensuremath{\gamma}$-coincidence measurements have been performed with a Ge(Li) detector in and perpendicular to the reaction plane. The angular distributions of the absolute double differential cross sections have been measured for particle angles between 30 and 150\ifmmode^\circ\else\textdegree\fi{}. It turned out that the differential as well as the double differential cross section for transitions with an $l$ transfer of 0 or 1 can be described well by the distorted-wave Born-approximation (DWBA) method. DWBA fails to describe the angular correlations of the $l=2$ transitions. The "$j$-forbidden" $l=4$ transitions leading to the ${\frac{7}{2}}^{+}$ state at 1.611 MeV and ${\frac{9}{2}}^{+}$ state at 3.399 MeV have been compared with Hauser-Feshbach predictions. While the differential cross section of the transition to the ${\frac{7}{2}}^{+}$ state is compatible with Hauser-Feshbach calculations, the double differential cross sections for both transitions cannot be described by Hauser-Feshbach theory. Potential ambiguities, arising from DWBA analyses of the differential cross sections could not be removed from the analyses of the double differential cross sections.[NUCLEAR REACTIONS $^{24}\mathrm{Mg}(d,p\ensuremath{\gamma})$, $E=10$ MeV; measured double differential cross sections. DWBA analyses of $l=0,1, \mathrm{and} 2$ transitions and Hauser-Fesh-bach analyses of $l=4$ transitions; enriched target.