Existence of alpha -cluster structure in 44Ti via the (6Li,d) reaction.

{alpha}-cluster states in {sup 44}Ti have been investigated in the {sup 40}Ca({sup 6}Li,{ital d}){sup 44}Ti reaction at {ital E}=50 MeV. The angular distributions of 34 levels at excitation energies for {ital E}{sub {ital x}}=0--13 MeV allow us to analyze the data. The angular distributions of positive-parity members of the ground-state band (the {ital K}{sup {pi}}=0{sup +} band) in {sup 44}Ti were well reproduced by the finite-range distorted-wave Born approximation calculations up to the transferred angular momentum of {ital L}=8. For the members of the negative-parity band (the {ital K}{sup {pi}}=0{sup {minus}} band) with the primary quantum number {ital N}=13, three levels at 6.22, 7.34, and 9.43 MeV were identified as the 1{sup {minus}}, 3{sup {minus}}, and 5{sup {minus}} states, respectively. The existence of a negative-parity band in {sup 44}Ti has been investigated for a long time and persistently gives considerable support to {alpha}-cluster models for nuclei heavier than {ital A}=40.