  The charge-exchange break-up of polarised deuterons pol{d}p -> {pp}n, where
the final {pp} diproton system has a very low excitation energy and hence is
mainly in the 1S0 state, is a powerful tool to probe the spin-flip terms in the
proton-neutron charge-exchange scattering. Recent measurements with the ANKE
spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended
these studies into the pion-production regime in order to investigate the
mechanism for the excitation of the Delta(1232) isobar in the pol{d}p -> {pp}X
reaction. Values of the differential cross section and two deuteron tensor
analysing powers, A_{xx} and A_{yy}, have been extracted in terms of the
momentum transfer to the diproton or the invariant mass Mx of the unobserved
system X. The unpolarised cross section in the high Mx region is well described
in a model that includes only direct excitation of the Delta isobar through
undistorted one pion exchange. However, the cross section is grossly
underestimated for low Mx, even when Delta excitation in the projectile
deuteron is included in the calculation. Furthermore, direct Delta production
through one pion exchange only reproduces the angular dependence of the
difference between the two tensor analysing powers.
