Energy dependence of analyzing powerAyand cross section forp+dscattering below 18 MeV

The vector analyzing power ${\mathit{A}}_{\mathit{y}}$(θ) of the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(p→,p${)}^2$H scattering has been measured at ${\mathit{E}}_{\mathit{p}}$=5, 6, 6.5, 7, 8, 8.5, 9, 10, 12, 14, 16, and 18 MeV with a typical statistical accuracy of 0.0009 and an uncertainty in the beam polarization of less than 0.7%. The differential cross section σ(θ) of the ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(p,p${)}^2$H scattering has also been measured with a typical uncertainty of 0.8% using unpolarized beams of the same energies and of 2, 2.5, 3, and 4 MeV. A large discrepancy of about 25% between the experiment and the Faddeev calculation with the Paris NN potential is observed at the maximum of ${\mathit{A}}_{\mathit{y}}$(θ) around ${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=120°. This discrepancy is shown to be reduced by modifying LS force in the NN potential, though a discrepancy still remains in the energy dependence of the ${\mathit{A}}_{\mathit{y}}$(θ) maximum. At the minimum of σ(θ) around ${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=120°, a large discrepancy ranging from -19% at 2 MeV to +24% at 18 MeV is observed between the experiment and the calculations with either of the original and the LS-modified NN potentials. This indicates that an improvement is also necessary in the scalar part of the potential. The difference in the ${\mathit{A}}_{\mathit{y}}$(θ) maximum between the p→+d and the n→+d scatterings is discussed.