Axial Observables in $\stackrel{\ensuremath{\rightarrow}}{d}\stackrel{\ensuremath{\rightarrow}}{p}$ Breakup and the Three-Nucleon Force

Axial Observables in $\vec{d} \vec{p}$ Breakup and the Three-Nucleon Force

H. O. Meyer, T. J. Whitaker, R. E. Pollock, B. von Przewoski, T. Rinckel, J. Doskow, J. Kuroś-Żołnierczuk, P. Thörngren-Engblom, P. V. Pancella, T. Wise, B. Lorentz, and F. Rathmann

Phys. Rev. Lett. 93, 112502 – Published 10 September 2004

Abstract

We have measured three axial polarization observables in $\vec{d} \vec{p}$ breakup with a polarized 270 MeV deuteron beam on a polarized proton target. Axial observables are zero by parity conservation in elastic scattering but can be easily observed in the breakup channel at the present energy. Based on a symmetry argument, the sensitivity of these observables to the three-nucleon force might be enhanced. Calculations without three-nucleon force are in fair agreement with our measurement, indicating that the expected sensitivity of axial observables to the three-nucleon force is not confirmed. Including a three-nucleon force in the calculation does not improve the agreement with the data.