Measurement of vector-tensor spin-transfer observables for the reaction H(p→,d→)π⁺ between 580 and 1300 MeV

The three polarization tensor components of the deuteron produced in the H(p→,d→)π⁺ reaction have been measured for the first time. The experiment was performed using a vertically polarized proton beam produced by the SATURNE accelerator. The deuteron polarization was measured with the POLDER polarimeter. The three polarizing powers t⁰⁰₂₀, t⁰⁰₂₁ and t⁰⁰₂₂ and the three spin-transfer observables t¹¹₂₀, t¹¹₂₁ and t¹¹₂₂ have been extracted at a proton kinetic energy of 580 MeV over a wide angular range and at two fixed center-of-mass angles, 132° and 151°, between 800 and 1300 MeV. The six observables, calculated in the C.M. helicity frame, have been compared with predictions of the most refined partial-wave analyses and also with the predictions of a theoretical coupled-channel model which includes the NN-NΔ transition. The comparison between the data and the theory/partial-wave analyses shows some discrepancies which get worse with increasing proton energy. Adding these data to the world database should improve significantly future partial-wave analyses. The A_y0 analyzing power has also been measured over the same kinematical range. The partial-wave analysis predictions are in good agreement with this observable.