Measurement of a complete set of analyzing powers and cross section of the kinematically complete breakup reaction 4He(d

The breakup reaction $^{4}\mathrm{He}$(d\ensuremath{\rightarrow},p\ensuremath{\alpha})n at ${\mathit{E}}_{\mathit{d}}$=7.0 MeV has been investigated in a kinematically complete experiment with vector and tensor polarized deuterons in a kinematical situation with zero relative energy of the two outgoing nucleons, a preferred situation to show effects from the singlet deuteron ${\mathit{d}}^{\mathrm{*}}$ and therefore isospin breaking. A complete set of analyzing powers, ${\mathit{A}}_{\mathit{y}}$, ${\mathit{A}}_{\mathit{y}\mathit{y}}$, ${\mathit{A}}_{\mathit{x}\mathit{z}}$, and ${\mathit{A}}_{\mathit{z}\mathit{z}}$ in addition to the differential breakup cross section, ${\mathit{d}}^{3}$\ensuremath{\sigma}/d${\mathrm{\ensuremath{\Omega}}}_{3}$d${\mathrm{\ensuremath{\Omega}}}_{4}$dS has been measured. The data are compared to new Faddeev calculations including an approximate (cutoff) Coulomb potential allowing for the ${\mathit{d}}^{\mathrm{*}}$ production and also D-wave \ensuremath{\alpha}-N interactions. Good agreement is found for the polarization observables and the shape of the cross section which, however, disagrees in absolute magnitude. Both the inclusion of the ${\mathit{d}}^{\mathrm{*}}$ and of D waves seem necessary for a good description of all data and for the interpretation of a small excursion in some observables in the n-p final-state interaction region as a manifestation of the isospin-forbidden ${\mathit{d}}^{\mathrm{*}}$.