Measurement of the Ayy tensor analyzing power for the 1H(d

Abstract

Measurements of the unpolarized triple differential cross section and the ${\mathit{A}}_{\mathit{y}\mathit{y}}$ tensor analyzing power for the $^{1}\mathrm{H}$(d,pp)n reaction were made using a 94.5 MeV polarized deuteron beam at the Indiana University Cyclotron Facility. Scattering angles (\ensuremath{\theta} and \ensuremath{\varphi}) and energy information were recorded for the two emerging protons using large-area wire chambers backed by stopping plastic scintillator detectors. Events were selected that were close to the symmetric constant relative energy geometry in order to enhance the sensitivity of the observables to off-shell and three-body effects. The measurements covered values of \ensuremath{\alpha}, the center-of-mass angle between the incoming proton and the outgoing neutron, from 72\ifmmode^\circ\else\textdegree\fi{} to 180\ifmmode^\circ\else\textdegree\fi{}. Comparisons are made to Faddeev calculations that use either separable potentials or an exact treatment of the S-wave nucleon-nucleon interaction in conjunction with a perturbative treatment of higher partial waves. While none of these calculations, which use only two-nucleon interactions, is completely satisfactory, there remains too much variation among different theoretical treatments to demonstrate the need for including additional dynamical features in the three-body model.