Experimental examination of the lowest alpha cluster states inTi44

Abstract

Two controversial states considered to have a large alpha cluster strength, the 0+ state at 8.54MeV and the 1 state at 11. 7 MeV of Ti, were examined in the ( Li,d) reaction at E( Li)=50MeV. The 11. 7-MeV state was scarcely observed, if at all, for Hl, b=5 -35', and the angular distribution for the 8.54-MeV state was unlike that of an L =0 transition. These results indicate that both states are unsuitable candidates for the lowest states of the parity doublet band of Ti in the alpha cluster model.

Isoscalar dipole transition as a probe for asymmetric clustering

“…where the principal quantum number N must be equal to or larger than N 0 + 1. The 1 − 1 state of 20 Ne at 5.8 MeV [67] and 1 − states of 44 Ti observed at 6.2 MeV and around 12 MeV [68,70,71] are attributed to this class of angular excited cluster state. Since the angular excitation with odd number angular momenta (negative-parity states) is allowed only in the asymmetric cluster systems (C 1 = C 2 ), the 1 − state has been regarded as the evidence of the asymmetric clustering [41].…”

“…In Fig. 3, by taking Around 12 MeV in excitation energy, another group of 1 − states having large α spectroscopic factors are reported [68,69,89]. Again, observed α spectroscopic factors are fragmented into several levels and the averaged value which we call the 1 − II state is shown in the figure.…”

“…Thus, the states with larger values of N are coherently superposed with coefficients e N . The 0 44 Ti observed around 11 MeV [68,69] are attributed to this class of nodal excited cluster states. In Ref.…”

“…The α + 40 Ca cluster states in 44 Ti have also been studied by many authors [68][69][70]79,[89][90][91][92][93][94][95][96][97][98], but the situation is more complicated than the case of 20 Ne. The theoretical and experimental studies are summarized in a review paper [99], and our discussion is based on the assignment given therein.…”

α-cluster excited states in32S

“…Typical example of the α-cluster excited states in Z = N nuclei are the 16 O + α cluster states in 20 Ne and 12 C + α cluster states in 16 O [25][26][27][28][29][30][31][32]. The α-cluster excited states are also suggested in the heavier mass nuclei such as 44 Ti and 40 Ca [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47].…”