We present new accurate measurements of the differential cross section σ(θ) and the proton analyzing power Ay for proton-3He elastic scattering at various energies. A supersonic gas jet target has been employed to obtain these low energy cross section measurements. The σ(θ) distributions have been measured at Ep = 0.99, 1.59, 2.24, 3.11, and 4.02 MeV. Full angular distributions of Ay have been measured at Ep = 1.60, 2.25, 3.13, and 4.05 MeV. This set of high-precision data is compared to four-body variational calculations employing realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. For the unpolarized cross section the agreement between the theoretical calculation and data is good when a 3N potential is used. The comparison between the calculated and measured proton analyzing powers reveals discrepancies of approximately 50% at the maximum of each distribution. This is analogous to the existing ``Ay Puzzle'' known for the past 20 years in nucleon-deuteron elastic scattering.
@article{arxiv.nucl-ex/0608024,
title = {Proton-$^{3}$He elastic scattering at low energies},
author = {B. M. Fisher and C. R. Brune and H. J. Karwowski and D. S. Leonard and E. J. Ludwig and T. C. Black and M. Viviani and A. Kievsky and S. Rosati},
journal= {arXiv preprint arXiv:nucl-ex/0608024},
year = {2007}
}
Comments
22 pages, 9 figures, to be published in Physical Review C, corrected reference 49