A. Boudard

Elastic scattering of polarized deuterons by protons at intermediate energies

Abstract The tensor analyzing power T 20 ( θ ) in dp backward scattering has been measured at or near center-of-mass angle θ = 180° in the energy range 0.3–2.3 GeV. A pronounced structure is observed around T d = 0.5 GeV which is explained by a predominant one-neutron-exchange mechanism. Other structures appear around 1 GeV and higher. They are not explained by calculations which include Δ-excitations in intermediate states. In addition, full angular distributions of vector A y and tensor A yy analyzing powers and differential cross sections have been obtained at 1.2 GeV and limited angular ranges explored at 0.5 GeV (back angles) and 1.6 GeV (forward angles).

Deuteron polarimetry studies at low and intermediate energies

Abstract A polarized deuteron beam has been developed at the Saturne 2 synchrotron for energies up to 2.3 GeV. Calibration of the vector and tensor polarization before injection is done with the d(d, p)t reaction induced by 386 keV deuterons. The possibility of depolarizing effects is discussed. Determination of the absolute analyzing powers using quasi-free proton-proton scattering, induced by high energy polarized deuterons, and the p(d , 3 He )π 0 reaction are described. New polarization standards are proposed.

Deuteron tensor analyzing power for the collinear dp → 3Heπ0 reaction at intermediate energies

Abstract The differential cross section and tensor analyzing power T 20 for p( d p → 3 He π 0 have been measured in the forward and backward directions at 19 energies between 500 MeV and 2.2 GeV. Significant structure in T 20 at 180° is related to the observed anomalous proton analyzing power. The large negative T 20 measured at low energies confirms that the capture of stopping pions on isoscalar nucleon pairs in 3 He is about an order of magnitude stronger than for isovector pairs.

Elastic scattering of polarized deuterons from 40Ca and 58Ni at intermediate energies

Abstract Angular distributions of cross section, and A y and A yy analyzing powers were measured for polarized deuteron elastic scattering from 58 Ni at 200, 400 and 700 MeV, and 40 Ca at 700 MeV. Phenomenological potentials were obtained from an optical model analysis of the data. The total reaction cross sections deduced were compared to predictions from the Glauber theory optical limit.

Cross section and deuteron analysing powers of the 1H(d, 2p)n reaction at 200 and 350 MeV

Abstract The cross section and analysing powers Ay, Axx and Ayy of the charge-exchange reaction 1 H ( d , 2 p ) n have been measured at Ed = 200 and 350 MeV up to excitation energies (Ex) of 8 MeV in the final pp system. The good agreement observed between the experimental dependence of the cross section and analysing powers upon Ex and the predictions of an impulse approximation calculation improves with increasing beam energy. The large experimental figures of merit found for Axx and Ayy demonstrate that this reaction can be used as the basis of a new deuteron tensor polarimeter in the 200–400 MeV energy range.

Measurements of vector and tensor analysing powers for 191 and 395 MeV deuteron scattering

Abstract Vector ( iT 11 ) and tensor ( T 20 and T 22 ) analysing powers for 191 and 395 MeV deuterons are reported for dp and dd elastic scattering and d-nucleus (Li, C, Ni, Pb) inclusive scattering with a rough selection on the outgoing deuteron energy. Applications to and the feasibility of intermediate energy deuteron polarimeters are discussed.

Measurements of tensor analyzing powers in the 1H(d, 2p)n reaction at 200 MeV

Abstract The cross section, the vector Ay and the two tensor analyzing powers Axx and Ayy have been measured for the 1H(d, 2p)n reaction at Ed = 200 MeV in the region of low p-p excitation energies. The agreement with the predictions of the plane wave impulse approximation calculation is, in general, very good up to a momentum transfer of q = 200 MeV c . The large cross section and significant tensor analyzing powers measured confirm that the reaction may be used as a basis of an efficient and convenient deuteron tensor polarimeter at intermediate energies.

Elastic scattering of polarised deuterons from 16O at 200, 400 and 700 MeV☆

Abstract Angular distributions of cross section, and A y and A yy analysing powers were measured for polarised deuteron elastic scattering from 16 O at 200, 400 and 700 MeV. The data at 200 MeV bear evidence of the nuclear rainbow phenomenon while those at 400 and 700 MeV are reminiscent of the proton scattering results at equivalent energies. The data were analysed in terms of the optical model. The real central potential shape changes from an attractive Woods-Saxon form at 200 MeV to a wine-bottle-bottom form with a repulsive interior at 700 MeV. The total reaction cross sections deduced display a clear nuclear transparency effect in the present energy domain in agreement with predictions from the Glauber theory optical limit. Comparison with previous results for 40 Ca and 58 Ni targets is made.

The T20 of the dp→ 3Heπ0 reaction at threshold and π absorption on a pair of nucleons

Abstract A measurement of the analyzing power T20 for the reaction d p→ 3 Heπ 0 at threshold is described. Connection between the data and the absorption of π0 at rest is established. The experimental results confirm the dominance of the π absorption by an isoscalar pair of nucleons.

Measurements of angular distributions of differential cross sections and analyzing powers of the reaction pp → dπ+ between 1.3 and 2.4 GeV

Abstract We have measured angular distributions of differential cross sections and analyzing powers ( A y ) of the reaction p p → d π + at six incident proton energies between 1.3 and 2.4 GeV. They confirm the rapid variations at √ s = 2.65 GeV suggested by earlier experiments. Deviations from a monotonic behavior are also found in the excitation functions of the differential cross section at t = 0 or where Θ π + (c.m.) = 0°. Structures clearly appear at √ s = 2.4 and 2.65 GeV, in some coefficients of the associated Legendre function expansions of A y .