A polarized proton beam extracted from SATURNE II and the Saclay polarized proton target were used to determine the spin correlation parameter Aoosk and the rescattering observablesK os″ so; Dos″ok, Nos″sn, andN onsk at 1.80 and 2.10 GeV. The beam polarization was oriented perpendicular to the beam direction in the horizontal scattering plane and the target polarization was directed either along the vertical axis or longitudinally. Left-right and up-down asymmetries in the second scattering were measured. A check for the beam optimization with the beam and target polarizations oriented vertically provided other observables, of which results forD onon andK onno at 1.80, 1.85, 2.04, and 2.10 GeV are listed here. The new data at 2.10 GeV suggest a smooth energy dependence of spin triplet scattering amplitudes at fixed angles in the vicinity of this energy.

New data on the spin-dependent np observables measured with quasi-monochromatic polarized neutron beam in the energy region from 1.2 to 3.7 GeV are presented. Further measurements of np scattering observables using the JINR LHE polarization facility (longitudinal and transverse polarized neutron beams and a polarized proton target) are discussed. The aim of these studies is to determine the imaginary and real parts of the forward scattering amplitudes for np and for isospin I=0 systems above 1.1 GeV.

Measurements at 18 beam kinetic energies between 1975 and 2795 MeV and at 795 MeV are reported for the pp elastic scattering spin correlation parameter A(00nn) = (N.N,0,0)= C-NN=A(NN). The c.m. angular range is typically 60 degrees -100 degrees. These results are compared to previous data from Saturne II and other accelerators. A search for energy-dependent structure at fixed c.m. angles is performed. Comparisons are made to phase shift analysis and theoretical model predictions of this spin observable.

New results for the np spin-dependent total cross section difference Δσ p ( np ) at neutron beam kinetic energies of 1.59, 1.79 and 2.20 GeV are presented. Measurements of the Δσ p ( np ) energy dependence were carried out at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. The values of Δσ L were measured as a difference between the np total cross sections for parallel and antiparallel beam and target polarizations, both oriented along the beam momentum. A fast decrease of Δσ p ( np ) with increasing energy above 1.1 GeV, as it was first seen from our previous data, was confirmed. The new results are also compared with model predictions and with the phase shift analysis fits. The Δσ L quantities for isosinglet state I=0, deduced from the measured values of Δσ p ( np ) and known Δσ p ( pp ) data, are given.

Method and results of the beam polarization measurements are presented. The measurements were carried out at the proton polarized beam of Saturne-II accelerator as well as at the JINR (Dubna) synchrophasotron vector polarized deuteron beam. The analysis of the elastic (quasi-elastic) pp-scattering polarization is used as a method of the polarization measurements. The energy range of the measurement is 1.0≤ T p ≤2.8 GeV for polarized proton and 1.66≤ T d ≤7.3 GeV for polarized deuteron beams.

Measurements at 18 beam kinetic energies between 1975 and 2795 MeV and at 795 MeV are reported for the pp elastic-scattering single spin parameter Aooon=Aoono=AN=P. The c.m. angular range is typically 60–100°. These results are compared to previous data from Saturne II and other accelerators. A search for energy-dependent structure at fixed c.m. angles is performed, but no rapid changes are observed.Received 1 June 1999DOI:https://doi.org/10.1103/PhysRevC.60.054002©1999 American Physical Society

A polarized proton beam from SATURNE II, the Saclay polarized targets with \(^6\)Li compounds, and an unpolarized \(\mathrm{CH}_2\) target were used to measure spin-dependent observables for protons scattered on bound nucleons. The beam and target polarizations were oriented vertically. The analyzing power \(A_{\mathrm{oono}}\) and the depolarization \(D_{\mathrm{nono}}\) were determined at seven energies between 1.1 and 2.4 GeV. The spin correlation parameter \(A_{\mathrm{oonn}}\) was measured at only 1.1 and 1.6 GeV. Measurements with the \(\mathrm{CH}_2\) target at 1.1 GeV provided \(A_{\mathrm{oono}}\) data for scattering of polarized protons on neutrons in carbon. The quasi-elastic observables are compared with previous elastic scattering measurements and at 1.1 GeV with predictions of phase shift analyses.

A polarized proton beam extracted from SATURNE II, the Saclay polarized target with \(^6\)Li compounds, and a \(\mathrm{CH}_2\) target were used to measure elastic and quasi-elastic pp spin-dependent observables in the angular region \(60^{\circ} < \theta_{\mathrm{CM}} < 105^{\circ}\). The beam and/or target polarizations were oriented vertically. Accurate pp data for the analyzing power \(A_{\mathrm{oono}}\), spin-correlation parameter \(A_{\mathrm{oonn}}\), and the polarization transfer \(K_{\mathrm{onno}}\) were measured at 1.1 GeV. The observables \(A_{\mathrm{oono}}\) and \(K_{\mathrm{onno}}\) were determined at six other energies between 1.6 and 2.4 GeV. At 1.6 GeV, \(A_{\mathrm{oonn}}\) was also obtained. The individual contributions from H, \(^6\)Li, and \(^6\)LiD were deduced. The \(\mathrm{CH}_2\) target provided \(A_{\mathrm{oono}}(\mathrm{pp})\) results on free hydrogen and on protons in carbon. The elastic and quasi-elastic observables are compared with existing data and with phase-shift analysis predictions.

Experimental results are presented for the pp elastic-scattering single spin observable A(oono)=A(ooon)=A(N) =P, or the analyzing power, at 19 beam kinetic energies between 1795 and 2235 MeV. The typical c.m. angular range is 60-100 degrees. The measurements were performed at Saturne II with a vertically polarized beam and target (transverse to the beam direction and scattering plane), a magnetic spectrometer and a recoil detector, both instrumented with multiwire proportional chambers, and beam polarimeters. [S0556-2813(99)03610-9].

A polarized proton beam extracted from SATURNE II and the Saclay polarized proton target were used to measure the rescattering observables $K_{onno}$ and $D_{onon}$ at 26 energies from 1.94 to 2.80 GeV and at 0.80 GeV. The beam and target polarizations were oriented vertically and left-right as well as up-down asymmetries in the second scattering on carbon were measured. The present data, obtained in small energy steps, are practically constant as a function of energy at 90°CM, where $K_{onno} = D_{onon}$ . These data will bring about important modification to phase shifts and stabilize the solutions.

A polarized proton beam extracted from SATURNE II was scattered on an unpolarized CH2 target. The angular distribution of the beam analyzing power Aoono was measured at large angles from 1.98 to 2.8 GeV and at 0.80 GeV nominal beam kinetic energy. The same observable was determined at the fixed mean laboratory angle of 13.9° in the same energy range. Both measurements are by-products of an experiment measuring the spin correlation parameter Aoon.

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.

The polarization of extracted SATURNE II proton beam as a function of different ion source configurations was studied. Two distinct experiments were necessary for this purpose. In the first one, the LEFT-RIGHT instrumental asymmetry of the beam polarimeter was determined using an unpolarized beam. In the second one this correction factor was applied to asymmetries measured with the beam from the polarized ion source in all polarization states. The measurements were carried out at the proton beam kinetic energy 0.80 GeV, where the pp-elastic scattering analyzing power is near its maximum. The results confirmed that the two so-called “unpolarized states” of the source were polarized to several percent, whereas the absolute values of the beam polarizations in the so-called “polarized states” were equal and opposite. It was observed that the hexapole lens of the ion source produced beam polarization in the absence of any transition. The beam polarization as a function of hexapole current, transition field attenuation, and spin rotation solenoid current was measured. It was also shown how to obtain a strictly unpolarized beam using the polarized source only. The results obtained with the SATURNE II ion source HYPERION may also be relevant to similar sources at other accelerators.

A SATURNE polarized target has been used for nucleon-nucleon elastic scattering and transmission experiments for 15 years. Continuous improvements resulted in a flexible and reliable facility for spin physics. The polarized proton target was a 70 cm3 cartridge loaded with pentanol-2, a promising material according to the results obtained. The new acquisition system and data processing was based on the LabView/PC software and increased the accuracy of polarization measurements. For a polarized neutron target, two cartridges loaded with 6LiD and 6LiH were set in the refrigerator and could be quickly inserted in the beam. Results from the the first experiments using 6Li materials in quasielastic pp or pn analyzing power measurements are compared with the same observables measured in free nucleon-nucleon scattering using polarized proton targets. The angular resolution distributions for θCM determination and azimuthal coplanarity are shown for different targets in nucleon-nucleon scattering. A comparison of analyzing power results for elastic and quasielastic scattering suggests that the contribution of inelastic processes to quasielastic pn scattering may be suppressed by additional constraints.

Results of the total cross section differenceΔσ L in anp transmission experiment at 1.19, 2.49 and 3.65 GeV incident neutron beam kinetic energies are presented. Measurements were performed at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. Results were obtained with a polarized beam of free quasi-monochromatic neutrons passing through the new Dubna frozen spin proton target. The beam and target polarizations were oriented longitudinally. The present results were obtained at the highest energies of free polarized neutrons that can be reached at present. They extend the energy range of existing results from PSI, LAMPF and Saclay measured between 0.066 and 1.10 GeV. The new results are compared withΔσ L(pn) data determined as a difference betweenΔσ L(pd) andΔσ L(pp) ANL-ZGS measurements. The values ofΔσ L for the isospin stateI=0 were deduced using knownpp data.

A movable polarized proton target is planned to be installed in polarized beams of the Synchrophasotron-Nuclotron complex in order to carry out a spin physics experimental program at Dubna. The project is described and the first proposed experiments are discussed.

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 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.