Strong L = O (T, P) Transitions In Even Isotopes Of Ti, Cr, And Fe

Absolute differential cross sections for strong $L=0 (t,p)$ transitions on targets of $^{46,\phantom{\rule{0ex}{0ex}}48,\phantom{\rule{0ex}{0ex}}50}\mathrm{Ti}$, $^{50,\phantom{\rule{0ex}{0ex}}52,\phantom{\rule{0ex}{0ex}}54}\mathrm{Cr}$, and $^{54,\phantom{\rule{0ex}{0ex}}56,\phantom{\rule{0ex}{0ex}}58}\mathrm{Fe}$ have been measured. The bombarding energy was 13 MeV and reaction angles of 12.5 and 20\ifmmode^\circ\else\textdegree\fi{} were used. The data are compared with model predictions, with special emphasis on the pairing-vibrational model with isospin. The latter model correctly predicts the dependence on neutron number of the ($t,p$) cross sections but fails, as do all other models, to predict the steady cross-section decrease with increasing $Z$. It is suggested that the latter effect is caused by a slow change in the ground-state correlations.