$\alpha$ cluster states in ${}^{44,46,52}$Ti

$\alpha$ decaying states of ${}^{44,46,52}$Ti were investigated with angular correlation functions between $t$ and $\alpha$ with the $^{40, 42, 48}$Ca($^7$Li,$t\alpha$)$^{40, 42, 48}$CareactionsatE=26.0MeV\mathrm{.}Many$\alpha$ cluster states were newly observed in the 10 - 15 MeV excitation energy of ${}^{44}$Ti and their spin-parities were assigned, in which $J^{\pi }=7^{-}$ state was found at 11.95 MeV as a candidate for the member of the $K=0_1^{-}$ negative parity band. In ${}^{46}$Ti many $\alpha$ cluster states were also found in the 11 - 17 MeV excitation energy with the ${}^{42}$Ca(${}^7$Li, $t\alpha$)${}^{42}$Ca reaction, though its strength is weak compared to ${}^{44}$Ti. No $\alpha$ cluster states were detected for the ${}^{48}$Ca(${}^7$Li, $t\alpha$)${}^{48}$Ca reaction, in which the number of coincidence events decaying from ${}^{48}$Ca was very small.