Lifetimes of the ${\left(f_{\frac{7}{2}}\right)}^3{\frac{15}{2}}^{-}$ states in ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ and ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ and ${\left(f_{\frac{7}{2}}\right)}^2{4}^{+}$ states in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ and ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$ via heavy-ion recoil-distance-method measurements

The recoil-distance method has been used in conjunction with heavy-ion reactions to measure the following mean lifetimes: $\tau =8.0\mathrm{}\pm 0.6 \mathrm{and} 34.1\pm 1.5$ psec for the ${\left(f_{\frac{7}{2}}\right)}^3$ (${\frac{15}{2}}^{-}$) states at 2700 keV in ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ and at 2754 keV in ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$, and $\tau =7.7\mathrm{}\pm 1.5 \mathrm{and} 5.1\pm 0.4$ psec for the ${\left(f_{\frac{7}{2}}\right)}^2{4}^{+}$ states at 2676 keV in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ and at 2752 keV in ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$, respectively. The resulting $B\left(E2\mathrm{}\right)\mathrm{}$ strengths are interpreted in terms of effective charges for different model spaces.

NUCLEAR REACTIONS ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n)$ $E=26\mathrm{}$ MeV, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, p3n)$ $E=26\mathrm{}$ MeV, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, 4n)$ $E=28\mathrm{}$ MeV, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}({}_{}{}^{18}{}_{}{}^{}\mathrm{O}, pn)$ $E=30, 35$ MeV, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}({}_{}{}^{18}{}_{}{}^{}\mathrm{O}, p2n)$ $E=30, 35$ MeV, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}({}_{}{}^{19}{}_{}{}^{}\mathrm{F}, 2pn)$ $E=36\mathrm{}$ MeV; measured recoil distance. Deduced $T_{\frac{1}{2}}$, $B\left(E2\mathrm{}\right)\mathrm{}$, effective charges. Natural and enriched targets, Ge(Li) detector.