The direct reconstruction of the neutron-proton elastic-scattering amplitudes was carried out at six energies from 0.80 to 1.1 GeV. At the five highest energies the complete sets of spin-dependent observables used were measured in the nucleon-nucleon experimental program at SATURNE II. At 0.80 GeV, LAMPF data were also used. The invariant amplitudes a,b,c,d, and e were fit to the experimental data using a least-squares method. A search for solutions starting from random initial values was performed to determine different possible sets of amplitudes. The real and imaginary parts at several angles are listed in tables and compared with the predictions of two phase shift analyses.

Neutron-proton total cross section differences with the beam and target polarizations orientated either transversally or longitudinally with respect to the beam direction, as well as 11 spin dependent elastic scattering observables measured at SATURNE II as a function of energy and angle are presented. A major part of results was measured using the quasimonoenergetic polarized neutron beam and/or the polarized proton target. A small part of data was obtained using a polarized deuteron beam considered as a beam of quasifree neutrons and protons. The present paper represents a review of measured observables. Several sets of present data are compared with results obtained in other laboratories below 0.8 GeV. Imaginary parts of spin dependent forward amplitudes for np scattering and for the isospin stateI=0 were determined. First direct reconstruction of the np scattering matrix at 0.84 GeV is shown.

We present a total of 191 and 203 data points of the elastic neutron-proton spin correlation parameters A(ookk) and A(oosk), respectively. Both observables were measured in a large angular interval. The observable A(ookk) was measured from 0.312 to 1.10 GeV and A(oosk) from 0.80 to 1.10 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the polarized Saclay frozen-spin proton target. The beam polarization was oriented either along the beam direction or sideways, the target polarization was oriented longitudinally. Data are compared with phase-shift analyses predictions and with the PSI, LAMPF and SATURNE II results. Present results provide an important contribution to any future theoretical or phenomenological analysis.

We present data of several rescattering observables measured in np elastic scattering between 0.80 and 1.10 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the Saclay polarized frozen-spin proton, target. Three different configurations of beam and target polarization directions were used: the observables D(onon) and K(onno) were measured with the normal-normal spin configuration at eight energies; N(onkk), D(os'' ok) and K(os'' ko) were determined with the longitudinal-longitudinal configuration at six energies; N(onsk), D(os'' ok) and K(os'' so) with the sideway-longitudinal configuration at six energies. Part of the data was obtained with an unpolarized CH2 target where only the two spin-index polarization transfer parameters K(os'' ko) and K(os'' so) were determined. Data are compared with phase shift analyses predictions and with the LAMPF results at 0.788 GeV. Present results are the first measurements of rescattering observables above 0.80 GeV. They provide an important contribution to any future theoretical or phenomenological analysis.

We present data of several rescattering observables measured inn p elastic scattering between 0.80 and 1.10 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the Saclay polarized frozen-spin proton target. Three different configurations of beam and target polarization directions were used: the observablesD onon andK onno were measured with the normal-normal spin configuration at eight energies;N onkk ,D os″ok andK os″ko were determined with the longitudinal-longitudinal configuration at six energies;N onsk ,D os″ok andK os″so with the sideway-longitudinal configuration at six energies. Part of the data was obtained with an unpolarized CH2 target where only the two spin-index polarization transfer parametersK os″ko andK os″so were determined. Data are compared with phase shift analyses predictions and with the LAMPF results at 0.788 GeV. Present results are the first measurements of rescattering observables above 0.80 GeV. They provide an important contribution to any future theoretical or phenomenological analysis.

The present article describes an apparatus used for the measurement of spin dependent observables at SATURNE II. Observables for np elastic and quasi-elastic scattering were measured between 0.31 and 1.1 GeV, those for pp elastic scattering between 1.94 and 2.24 GeV. Measurements of pn and pp observables with an unpolarized 6LiD and 7LiH targets around 2 GeV were also carried out. Fast electronics, on-line data acquisition, event selection and off-line analysis are presented.

We present a total of 427 np analyzing power data points in a large angular interval at 12 energies between 0.312 and 1.10 GeV. The SATURNE II polarized beam of free monochromatic neutrons was scattered either on the Saclay frozen-spin polarized proton target or on CH2 and C targets. Present results are compared with existing elastic and quasieleastic data.

We present a total of 273 independent data points of the analyzing powers Aoono (nP) and Aooon (nP) in a large angular interval at four energies between 0.477 and 0.940 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the polarized Saclay frozen-spin proton target. Part of the data was obtained with a CH2 target. A comparison of the two measured observables allows one to determine the polarization of the neutron beam. The present results provide an important contribution to any future theoretical or phenomenological analysis.

We present a total of 323 data points of the spin correlation parameter Aoonn(np) in a large angular interval at eight energies between 0.8 and 1.1 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was scattered on the polarized Saclay frozen-spin proton target. The present data are the first existing results above 0.8 GeV.

Final results for total cross section differences ΔσT and ΔσL measured with a polarized neutron beam transmitted through a polarized proton target are presented. Measurements were carried out at SATURNE II, at 11 energies between 0.63 and 1.1 GeV for ΔσT and at 9 energies between 0.312 and 1.1 GeV for ΔσL. The results are compared with measurements at PSI and LAMPF as well as with ΔσL data points deduced from p-d and p-p transmission experiments at the ANL-ZGS. The present results together with the corresponding pp data allow to determine two of the three imaginary parts of forward scattering amplitudes for isospin I = 0.

The aim of the Nucleon-Nucleon program is to obtain the Nucleon-Nucleon amplitudes, either via Phase Shift Analyses or direct reconstruction. To this end, a large number of polarization observables, including spin transfer and 3-spin parameters, have been measured at Saturne II in neutron-proton elastic scattering, between 800 and 1100 MeV, using the free polarized neutron beam, obtained by breaking up of polarized deuterons. The analysis is still in a early stage, but, nevertheless, it has already been possible to reconstruct the neutron-proton amplitudes at 3 angles, at 840 and 880 MeV.

The direct reconstruction of the elastic scattering amplitudes at eleven energies between 0.83 and 2.7 GeV is described. Complete sets of spin dependent observables used for this reconstruction were measured in the nucleon-nucleon experimental program at Saturne II. The invariant amplitudes a, b, c, d and e were deduced using the least square method fit to the experimental data. A search for solutions starting from random initial values was performed to determine different possible sets of amplitudes. The absolute values show a similar angular dependence at all energies and for all solutions. The dependence of phases show discrete ambiguities especially at the higher energies. One of the solutions at 2.1 GeV suggests a behaviour which could be related to a dibaryon resonance of mass 2.73 GeV with the half-width at the half-maximum less than 50 MeV.

The spin-dependent observables D0n0n and K0nn0 in pp elastic scattering were measured at 11 energies between 0.84 and 2.7 GeV using the SATURNE II polarized proton beam and the Saclay frozen-spin polarized target. The beam and target polarizations were oriented along the normal to the scattering plane. Below 1 GeV the present data agree with previously existing measurements. Below 1.3 GeV they are compared with the predictions of the Saclay-Geneva phase-shift analysis. The results will improve the phase-shift analysis solutions and will contribute to their extension towards higher energies.

The spin-dependent observables N0nkk, D0s″0k and K0s″k0 in pp elastic scattering were measured at 11 energies between 0.84 and 2.7 GeV using the SATURNE II polarized proton beam and the Saclay frozen-spin polarized target. The beam and target polarizations were oriented longitudinally. Precession of the recoil-particle spin in the target holding field introduces small contributions from other parameters. The present data agree with the few previously existing measurements. Below 1.3 GeV our data are compared with the predictions of the Saclay-Geneva phase-shift analysis. The new results will considerably affect the phase-shift analysis solutions and will contribute to their extension towards higher energies.

The spin correlation parameters A00kk and A00sk were measured at 0.874, 0.934, 1.095, 1.295, 1.596, 1.796, 2.096, and 2.396 GeV, using the SATURNE II polarized proton beam and tha Saclay frozen spin polarized target. The present results for beam-target spin correlations obtained during measurements of three-spin index observables confirm, in particular, relatively large positive values of A00sk at certain energies and angles, as was shown in previously published data from a dedicated experiment.

For n‐p scattering we present the existing data for ΔσL, ΔσT and Aookk(np) quantities. For pp elastic scattering we present a direct reconstruction of the isospin I=1 scattering amplitudes in the energy region from 0.84 to 2.7 GeV. The results of this reconstruction suggest a structure in several amplitudes near 2.1 GeV. The existence of this structure was tested in a dedicated experiment.

The spin dependent observables N0sn″k, K0s″s0 and D0s″0k in pp elastic scattering were measured at 11 energies between 0.84 and 2.7 GeV using the SATURNE II polarized proton beam and the Saclay frozen spin polarized target. The beam polarization was oriented in the vertical plane, the target polarization was oriented along the incident beam direction. Below 1 GeV the present data agree with previously existing measurements. Below 1.3 GeV they are compared with the predictions of the Saclay-Geneva phase shift analysis. The results will improve the phase shift analysis solutions and will contribute to their extensions towards higher energies. Together with our previous results the data allow a direct reconstruction of the pp elastic matrix over the energy region from 0.84 too 2.7 GeV.

The spin-dependent observables N0s″kn, D0n0n and K0s″k0 in pp elastic scattering were measured at nine energies between 0.84 and 2.1 GeV using the SATURNE II polarized proton beam and the Saclay frozen spin polarized target. The beam polarization was oriented longitudinally and the target polarization was oriented vertically. Precession of the recoil particle spin in the target holding field introduces a small contribution from other parameters. The present results for K0s″k0 and D0n0n agree with our previous measurements of the same observables carried out in different beam and target spin configurations as well as with previously existing measurements. The observable N0s″kn had not been measured previously above 0.58 GeV. Below 1.3 GeV our data are compared with the predictions of the Saclay-Geneva phase shift analysis. The new results will considerably affect the phase shift analysis solutions and will contribute to their extension towards higher energies.

The spin correlation parameter Aookk in pp elastic scattering was measured using the SATURNE II polarized proton beam and the Saclay frozen spin polarized target. The measurements at 0.88 and 1.1 GeV were carried out in the angular region θCM from 28° to ⋍ 50° and complete our previous measurements from 45° to 90°. Above 1.1 GeV the measurements presented here cover both regions, extending from θCM = 28° (at the lower energies) or θCM = 18° (at the higher energies) to θCM > 90°. The shape of the angular distribution Aookk (pp) = f(θCM) changes considerably between in our energy region.