We evaluate two dominant nuclear reaction rates and their uncertainties that affect ^ { 44 } Ti production in explosive nucleosynthesis .
Experimentally we develop thick-target yields for the ^ { 40 } Ca ( \alpha , \gamma ) ^ { 44 } Ti reaction at E _ { \alpha } = 4.13 , 4.54 , and 5.36 MeV using \gamma -ray spectroscopy .
At the highest beam energy , we also performed an activation measurement which agrees with the thick target result .
From the measured yields a stellar reaction rate was developed that is smaller than current statistical-model calculations and recent experimental results , which would suggest lower ^ { 44 } Ti production in scenarios for the \alpha - rich freeze out .
Special attention has been paid to assessing realistic uncertainties of stellar reaction rates produced from a combination of experimental and theoretical cross sections .
With such methods , we also develop a re-evaluation of the ^ { 44 } Ti ( \alpha , p ) ^ { 47 } V reaction rate .
Using these two rates we carry out a sensitivity survey of ^ { 44 } Ti synthesis in eight expansions representing peak temperature and density conditions drawn from a suite of recent supernova explosion models .
Our results suggest that the current uncertainty in these two reaction rates could lead to as large an uncertainty in ^ { 44 } Ti synthesis as that produced by different treatments of stellar physics .