Measurement of a complete set of analyzing powers of the fusion reactions D( $$\vec d$$ ,p)3He atE d=28 keV

Angular distributions of the four analyzing powers of the mirror fusion reactions D(\(\vec d\),p)3H and D(\(\vec d\),n)3He have been measured at the very low energy of 28±3 keV. Differences between both reactions are visible. The data are compared with anR-matrix parametrization and used as input to a comprehensive reaction-matrix fit.D-wave contributions are strongly suppressed in contrast toP- andS-waves. However, entrance-channel quintetS-waves are not suppressed. The possibility of a neutron-lean fusion reactor is therefore excluded.