Difference between nd Ay and pd Ay below 16 MeV

Analyzing power Ay(θ) of nd scattering was accurately measured at En=12 and 16 MeV. Polarization of the n-beam produced by spin transfer 2H(d,n)3He reaction at 0° was determined in a separate experiment using 4He(n,n) scattering. The present nd Ay(θ) data are consistent with the existing nd Ay(θ) data below En=14.1 MeV. It was confirmed that the difference between nd Ay and pd Ay becomes large above 14 MeV and the assumption on slow-down effects by Coulomb force breaks down. The observed large difference in Ay(θ) requires systematic calculations with exact treatment of Coulomb force to study charge symmetry in nuclear force.